I recently migrated my personal emails from Google Gmail to Microsoft Outlook. This migration also required me to transfer all of my Google-hosted emails to Microsoft. To convert the whole mailbox from one account provider to another, I utilised a Microsoft Outlook for Mac device running the most recent version of macOS and Outlook 16.6. (latest version at the time of writing this blogpost).
Sadly, some of the transferred e-mails appeared in the Sync Error window and displayed an error message. These error messages featured information about the e-mail (the subject line), the time at which the synchronisation fault occurred, the error message itself, the specifics of this error message, and a cryptic error code. I have encountered the following error messages:
- Error: Could not synchronise record. Operation would change object type, which is not permitted. Error code: -19703
- Error: Could not synchronise record. ChangeKey is required for this operation. Error code: -19928
- Error: Could not synchronize record. Property is not valid for this object type. Error code: -19803
Solution 1: Empty the Cache
In my case, approximately 100,000 emails were transferred from one mailbox to another in a matter of hours during the migration of my emails. The Outlook programme must organise the transfer, and there is always the possibility that something will go wrong with the Outlook mail program’s cache. You should at least attempt to clear the cache to determine if the problem persists.
- Ensure you don’t work in Off-line mode first.
- In the navigation pane, right-click the Exchange folder for which you want to empty the cache, and then click Properties.
- On the General tab, click Empty Cache. The folder will be emptied, so be prepared because Outlook will automatically download all the email items again from the Exchange server.
Try also to restart Microsoft Outlook at this point (fully quit the application and open it again).
Solution 2: Delete These Items Manually
Typically, the impacted items contain special characters, are out of office (automatic replies), RSVP calendar replies, or are other unique sorts of email that prevent syncing.
Given the volume of emails that have failed to synchronise, it may be prudent to manually locate and delete these messages. Furthermore confirm that they are removed from the trash / deleted items folder, as the error message may persist if they remain there.