Mac For Outlook 2016 Sync Error

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• Outlook
• Outlook 2016 For Mac Standalone
• Mac For Outlook 2016 Sync Error User
• Mac Outlook 2016 Sync Errors

Original KB number: 2872257

I'm running Outlook for Mac Version 15.37 on OSX 10.11.16. For the past couple of weeks I've had this issue with attempting to send emails. It only occurs sporadically. I get several sync errors and the email I'm trying to send gets hung up in the Outbox. When I go to the Sync Errors menu I get the following messages. See image below. In Outlook, click Help Check For Updates. If an update is found, download and install it. Restart Outlook. If the problem continues, click Help Contact Support.

Summary

Outlook for Mac provides the option to enable logging for the following features:

• AutoDiscover service
• Microsoft Exchange (folder and item synchronization)
• Microsoft Exchange Calendar
• LDAP transactions

Outlook

In Outlook 2016 for Mac version 15.12.3 and later versions, the following features are also logged in addition to those listed earlier:

• Database
• IMAP
• Network Connections
• Import
• Upgrade
• Sync

More information To enable logging in Outlook 2016 for Mac, follow these steps

Enable logging

• On the Window menu, select Sync Errors.
• In the Sync Errors window, select the Gear icon.
• Select the Turn on logging for troubleshooting option, and then select OK.
• Restart Outlook and when prompted to turn off logging select Leave Logging On and reproduce the issue you experience and then Quit Outlook to stop the log capture

To disable logging:

• Restart Outlook and when prompted to turn off logging, select Turn Logging Of. If you disable logging manually, you must restart Outlook to fully disable logging, otherwise it will continue logging in the background.

To enable logging in Outlook for Mac 2011, follow these steps

Enable logging

• On the Window menu, select Error Log.
• In the Error window, select the Gear icon.
• Select the Turn on logging for troubleshooting option, and then select OK.
• Close the Error window.

To disable logging:

• Restart Outlook and when prompted to turn off logging select Turn Logging Off. If you disable logging manually you must restart Outlook to fully disable logging, otherwise it will continue logging in the background.

Note

It is important to turn off logging after you complete your troubleshooting and reproduce the issue. If logging is not turned off, the log files size will continue to increase. If you must keep logging enabled for several hours or several days in order to capture the issue, make sure that the hard disk has sufficient free space.

Log file locations

Depending on the edition and version of Outlook for Mac in which the log is being collected, the log name and location will differ. To locate the log, see the following table.

Outlook for Mac edition	Version	Location	File name
Outlook for Mac 2011	14.0.0 - 14.2.4	~/Desktop/	Microsoft Outlook_Troubleshooting_0.log
Outlook for Mac 2011	14.2.5 - current	~/Desktop/OfficeLogging/	Microsoft Outlook_Troubleshooting_#.csv
Outlook 2016 for Mac	15.3 - 15.11.2	~/Library/Group Containers/ UBF8T346G9.Office/OfficeLogging/	Microsoft Outlook_Troubleshooting_#.csv
Outlook 2016 for Mac	15.12.3 - Current	~/Library/Containers/com.microsoft.Outlook/Data/Library/Logs/	Microsoft outlook-<date>-<time>.log

Note

The character combination '~/' in the Location column in this table refers to the Home folder of the user. This folder is located under the Users folder on the root of the hard disk.

Important

In Outlook for Mac 2011 version 14.2.4 and earlier versions, data was appended to the same log file for every Outlook session. In Outlook for Mac 2011 version 14.2.5 and later versions and in Outlook 2016 for Mac, every time that you quit and start Outlook when logging is enabled, a new log file is created.

Viewing the log file

When you collect and send the log file, Microsoft Customer Service and Support uses it to identify issues. If you are a messaging server administrator, you can use the information in the log file to diagnose issues when you troubleshoot.

The log file contains the following information:

• Issues that occur when email messages, calendar items, notes, tasks, and meeting requests are sent or received.
• Type or severity of errors, if known.

In the Outlook for Mac log collected for Outlook for Mac 2011 and Outlook 2016 for Mac through version 15.11.2, each entry has a name that identifies the feature that is being logged. The following table lists the label for each feature.

Feature	Label that identifies the feature in the log file
AutoDiscover service	Outlook Exchange Auto Configure
Exchange (folder and item synchronization)	Outlook Exchange Web Services
Exchange Calendar	Outlook Calendar
LDAP transactions	Outlook LDAP

In Outlook 2016 for Mac version 15.12.3 and later versions, the log file opens in the Console and you can view it while Outlook is running. Each entry has a name that identifies the feature that is being logged. The following table lists the label for each feature.

Feature	Label that identifies the feature in the log file
AutoDiscover service	outlook.account.exchange.addaccount.config
Exchange (folder and item synchronization)	outlook.exchange.ews
Exchange Calendar	outlook.calendar
LDAP transactions	outlook.account.ldap
Database	outlook.database
IMAP	outlook.account.imap
Network Connections	outlook.network
Import	outlook.import
Upgrade	outlook.database.upgrade
Sync	outlook.sync

Note

The log file may also contain user information. This includes user name, sender and receiver's email addresses, and the contents of the user's email messages, notes, tasks, calendar, and contacts. Microsoft does not use this information to contact users without their consent. If you are concerned that the data file contains sensitive or confidential information, you may review the contents of the data file by using text-editing software and then remove the information from the file before you send the data file to support professionals. Authentication information is not included in the log files.

EWS SyncState message size

Starting with the Outlook for Mac 2011 14.3.4 update, the size of the SyncState binary large object (BLOB) of EWS messages increased from 6 kilobytes (KB) to 32 KB and can be increased up to no more than 300 KB. If you are troubleshooting an issue in which you have to view more of this data, you must increase this value. To increase the default value of the SyncState binary large object of EWS messages, follow these steps:

1. Exit Outlook 2011.

2. Enable java for mac firefox. Open Terminal.

3. To set the SyncState binary large object of EWS messages to a specific size, type the following command in Terminal window:

   Note

   The placeholder <max bytes> represents a byte value. For example, if you want to change the maximum byte size to 10 KB, you would type the value 10240.

4. To set the SyncState binary large object of EWS messages back to the default size of 32 KB, type the following command in Terminal window:

5. Start Outlook, and then enable Outlook logging.

Reading Time: 6minutes Pre-Flight Check Outlook 2016 For Mac Standalone

• These instructions are intended specifically for setting up a new email account in Microsoft Outlook 2016 for Mac OS X 10.11.3.
• If you have not already created an email address on your server, visit our New User Tutorial: Creating E-Mail Addresses in cPanel.
• If you need to configure your email address in Outlook 2016 for Microsoft Windows, see How To Set Up Email in Outlook 2016. For other mail clients, check out our tutorial on setting up other email clients.

Step #1: Add or Edit the Email Account

1. To set up a new email account or edit the settings on an existing one, click the Tools menu and then select Accounts to open the Accounts panel.
2. The setup process is slightly different depending on whether you have any existing email accounts configured in Outlook 2016:
   • Setting up your first email account: If this is your first time setting up Outlook 2016, you will need to click on the envelope icon next to the third option: Other Email (iCloud, Google, Yahoo!, or other accounts):
   • Setting up an additional email account: Once any email account has been set up in Outlook 2016, additional accounts can be added by clicking the plus sign in the lower left corner and selecting Other Email… from the pull-down menu:
   • Changing the settings for an existing email account: Click on the account’s name in the account list on the left to make changes to any existing account in Outlook 2016, and skip ahead to Step #4: Editing an Existing Email Account.
     Note: You cannot edit an existing email account to directly change its connection method. To change an account from POP to IMAP or vice versa, simply add a new account for the email address as described below and select the desired connection type. Outlook 2016 will allow you to have multiple accounts for the same email address, so an account for sample@example.com using IMAP can coexist with an account for sample@example.com using POP. To prevent data loss, do not delete the existing account before adding a new one.

Step #2: Configuring a New Email Account On the account information panel, enter the information as follows:

• E-mail address: requires your complete email address, such as sample@example.com.
• Password: is the password associated with the email account.
• User Name: is your full email address. It should exactly match what you entered into the E-mail address field above.
• Type: you may select IMAP or POP. IMAP is recommended for its ability to sync messages between multiple devices (to learn more about the difference between the protocols, see IMAP vs POP3 email).
• Incoming server:
  • When using standard (non-SSL) settings, use mail.yourdomainname.com
  • When using secure (SSL) settings, use the server’s hostname (host.yourdomainname.com)
  • The default port numbers should not need to be changed unless you have configured your server to use non-standard ports (not common)
  • Check the box next to Use SSL to connect (recommended)
• Outgoing server:
  • When using standard (non-SSL) settings, use mail.yourdomainname.com
  • When using secure (SSL) settings, use the server’s hostname (host.yourdomainname.com)
  • The default port numbers should not need to be changed unless you have configured your server to use non-standard ports (not common)
  • Check the box next to Use SSL to connect (recommended)

Once you’ve entered all the requested information, click the Add Account button at the bottom of the window to create the account with your specified settings. Step #3: Configure Security Settings When you add your email account, an alert window may prompt you to review security settings. This is expected if you have not already purchased and installed a signed, third-party verified SSL certificate on your mail server. If you see no such prompt, then you’re all set and can begin using Outlook 2016 with your email account immediately.If you do get a security prompt, which specifies that information that you view and send will be encrypted, note that Outlook 2016 will not be able to verify the security of the certificate through a third-party because you are the only authority validating it:If you wish to proceed with the connection, you have two options:

• You can click the Continue button to proceed, with the caveat that you may need to accept the warning each time Outlook connects.
• Or, you can permanently store the certificate and treat it as trusted, by clicking Show Certificate and then checking the box next to Always trust … before clicking Continue. You will need to authenticate with your password to store the exception for your self-signed certificate.

Once connected, Outlook 2016 will download your mail from the server along with any custom directories you’ve added, which will be synced by default. Step #4: Editing an Existing Email Account To change the settings on an existing email account, click the

The log file contains the following information:

• Issues that occur when email messages, calendar items, notes, tasks, and meeting requests are sent or received.
• Type or severity of errors, if known.

In the Outlook for Mac log collected for Outlook for Mac 2011 and Outlook 2016 for Mac through version 15.11.2, each entry has a name that identifies the feature that is being logged. The following table lists the label for each feature.

Feature	Label that identifies the feature in the log file
AutoDiscover service	Outlook Exchange Auto Configure
Exchange (folder and item synchronization)	Outlook Exchange Web Services
Exchange Calendar	Outlook Calendar
LDAP transactions	Outlook LDAP

In Outlook 2016 for Mac version 15.12.3 and later versions, the log file opens in the Console and you can view it while Outlook is running. Each entry has a name that identifies the feature that is being logged. The following table lists the label for each feature.

Feature	Label that identifies the feature in the log file
AutoDiscover service	outlook.account.exchange.addaccount.config
Exchange (folder and item synchronization)	outlook.exchange.ews
Exchange Calendar	outlook.calendar
LDAP transactions	outlook.account.ldap
Database	outlook.database
IMAP	outlook.account.imap
Network Connections	outlook.network
Import	outlook.import
Upgrade	outlook.database.upgrade
Sync	outlook.sync

Note

The log file may also contain user information. This includes user name, sender and receiver's email addresses, and the contents of the user's email messages, notes, tasks, calendar, and contacts. Microsoft does not use this information to contact users without their consent. If you are concerned that the data file contains sensitive or confidential information, you may review the contents of the data file by using text-editing software and then remove the information from the file before you send the data file to support professionals. Authentication information is not included in the log files.

EWS SyncState message size

Starting with the Outlook for Mac 2011 14.3.4 update, the size of the SyncState binary large object (BLOB) of EWS messages increased from 6 kilobytes (KB) to 32 KB and can be increased up to no more than 300 KB. If you are troubleshooting an issue in which you have to view more of this data, you must increase this value. To increase the default value of the SyncState binary large object of EWS messages, follow these steps:

1. Exit Outlook 2011.

2. Enable java for mac firefox. Open Terminal.

3. To set the SyncState binary large object of EWS messages to a specific size, type the following command in Terminal window:

   Note

   The placeholder <max bytes> represents a byte value. For example, if you want to change the maximum byte size to 10 KB, you would type the value 10240.

4. To set the SyncState binary large object of EWS messages back to the default size of 32 KB, type the following command in Terminal window:

5. Start Outlook, and then enable Outlook logging.

Reading Time: 6minutes Pre-Flight Check Outlook 2016 For Mac Standalone

• These instructions are intended specifically for setting up a new email account in Microsoft Outlook 2016 for Mac OS X 10.11.3.
• If you have not already created an email address on your server, visit our New User Tutorial: Creating E-Mail Addresses in cPanel.
• If you need to configure your email address in Outlook 2016 for Microsoft Windows, see How To Set Up Email in Outlook 2016. For other mail clients, check out our tutorial on setting up other email clients.

Step #1: Add or Edit the Email Account

1. To set up a new email account or edit the settings on an existing one, click the Tools menu and then select Accounts to open the Accounts panel.
2. The setup process is slightly different depending on whether you have any existing email accounts configured in Outlook 2016:
   • Setting up your first email account: If this is your first time setting up Outlook 2016, you will need to click on the envelope icon next to the third option: Other Email (iCloud, Google, Yahoo!, or other accounts):
   • Setting up an additional email account: Once any email account has been set up in Outlook 2016, additional accounts can be added by clicking the plus sign in the lower left corner and selecting Other Email… from the pull-down menu:
   • Changing the settings for an existing email account: Click on the account’s name in the account list on the left to make changes to any existing account in Outlook 2016, and skip ahead to Step #4: Editing an Existing Email Account.
     Note: You cannot edit an existing email account to directly change its connection method. To change an account from POP to IMAP or vice versa, simply add a new account for the email address as described below and select the desired connection type. Outlook 2016 will allow you to have multiple accounts for the same email address, so an account for sample@example.com using IMAP can coexist with an account for sample@example.com using POP. To prevent data loss, do not delete the existing account before adding a new one.

Step #2: Configuring a New Email Account On the account information panel, enter the information as follows:

• E-mail address: requires your complete email address, such as sample@example.com.
• Password: is the password associated with the email account.
• User Name: is your full email address. It should exactly match what you entered into the E-mail address field above.
• Type: you may select IMAP or POP. IMAP is recommended for its ability to sync messages between multiple devices (to learn more about the difference between the protocols, see IMAP vs POP3 email).
• Incoming server:
  • When using standard (non-SSL) settings, use mail.yourdomainname.com
  • When using secure (SSL) settings, use the server’s hostname (host.yourdomainname.com)
  • The default port numbers should not need to be changed unless you have configured your server to use non-standard ports (not common)
  • Check the box next to Use SSL to connect (recommended)
• Outgoing server:
  • When using standard (non-SSL) settings, use mail.yourdomainname.com
  • When using secure (SSL) settings, use the server’s hostname (host.yourdomainname.com)
  • The default port numbers should not need to be changed unless you have configured your server to use non-standard ports (not common)
  • Check the box next to Use SSL to connect (recommended)

Once you’ve entered all the requested information, click the Add Account button at the bottom of the window to create the account with your specified settings. Step #3: Configure Security Settings When you add your email account, an alert window may prompt you to review security settings. This is expected if you have not already purchased and installed a signed, third-party verified SSL certificate on your mail server. If you see no such prompt, then you’re all set and can begin using Outlook 2016 with your email account immediately.If you do get a security prompt, which specifies that information that you view and send will be encrypted, note that Outlook 2016 will not be able to verify the security of the certificate through a third-party because you are the only authority validating it:If you wish to proceed with the connection, you have two options:

• You can click the Continue button to proceed, with the caveat that you may need to accept the warning each time Outlook connects.
• Or, you can permanently store the certificate and treat it as trusted, by clicking Show Certificate and then checking the box next to Always trust … before clicking Continue. You will need to authenticate with your password to store the exception for your self-signed certificate.

Once connected, Outlook 2016 will download your mail from the server along with any custom directories you’ve added, which will be synced by default. Step #4: Editing an Existing Email Account To change the settings on an existing email account, click the Tools menu and then select Accounts to open the Accounts panel.Click on the name of the account in the left pane, and make the desired changes:

• User Name: is your full email address. It should exactly match the value of the E-mail address field above.
• Password: is the password associated with the email account.
• Incoming server:
  • When using standard (non-SSL) settings, use mail.yourdomainname.com
  • When using secure (SSL) settings, use the server’s hostname (host.yourdomainname.com)
  • The default port numbers should not need to be changed unless you have configured your server to use non-standard ports. If you do need to configure mail on a different port, you can check the box next to Override default port and enter the appropriate incoming mail server value (POP3 should be 110 for non-SSL connections and 995 when using SSL; IMAP should be 143 for non-SSL connections and 943 when using SSL.)
  • Check the box next to Use SSL to connect (recommended) for a secure connection.
• Outgoing server:
  • When using standard (non-SSL) settings, use mail.yourdomainname.com
  • When using secure (SSL) settings, use the server’s hostname (host.yourdomainname.com)
  • The default port numbers should not need to be changed unless you have configured your server to use non-standard ports. If you do need to configure mail on a different port, you can check the box next to Override default port and enter the appropriate outgoing mail server value (25 for non-SSL connections and 465 when using SSL; Unlike many other mail clients, Outlook 2016 does not require you to use port 587 on Mac OS X).
  • Check the box next to Use SSL to connect (recommended) for a secure connection.
  • The More Options… button will allow you to configure authentication for the outgoing (SMTP) mail server:
    • Authentication: Typically, Use Incoming Server Info is sufficient, but if you receive connection errors due to SMTP authentication, you may need to select User Name and Password. Do not select None; you will not be able to send mail if None is selected as the authentication type.
    • User Name: This field can only be filled in if you use the User Name and Password authentication type. If enabled, it must be the full email address.
    • Password: This field can only be filled in if you use the User Name and Password authentication type. If enabled, use the email account’s password.

Bonus: Select IMAP Folders to Sync By default, Outlook 2016 for Mac OS X will sync all IMAP folders. To specify which ones you want to sync, pull down under the Tools menu and select Mac For Outlook 2016 Sync Error User IMAP Folders… to bring up the Folder Browser.In the Folder Browser, you will see a list of your accounts in the left pane. Mac Outlook 2016 Sync Errors

• In the first pane, click on the IMAP account’s name
• In the second pane, click on INBOX (or the desired custom folder, if listed)
• In the third pane, click on the folder to which you want to subscribe or unsubscribe.
• Folders to which you already are subscribed will be displayed in bold type, while folders to which you are not currently subscribed will be displayed in a light-face font. Note that on some versions of Mac OS X, the distinction can be almost imperceptible.
• Clicking on the name of a folder to which you are subscribed will allow you to click the red ( – ) Unsubscribe button in the top-left menu, and clicking on the name of a folder to which you are not subscribed will allow you to click on the green ( + ) Subscribe button in the top-left menu.
• You can not unsubscribe to default account folders, such as Drafts, Junk, Sent, and Trash.