Summary
What do I do if I get the error Outlook.ost data file has reached its maximum size?
Who is Affected?
Users who have large mailboxes that use cache exchange mode in Outlook.
Symptoms and Signs
Outlook.ost data file has reached its maximum size. " Cannot postpone the reminder. The outlook.ost data file has reached the maximum size. To reduce the amount of data in this file, permanently delete some items that you no longer need.
Workaround (if available)
If you received that error, Outlook has not run out of space, the device maybe set to cache mode which will prevent emails from being moved or deleted from the that specific mailbox. To resolve the issue do the following below.
Click File > Account Settings > Account Settings.
Click the Exchange or Microsoft 365, and then click Change.
Under Offline Settings, uncheck Use Cached Exchange Mode.
(If you're a Microsoft 365 subscriber with semi-annual updates, under Offline Settings, uncheck Use Cached Exchange Mode to download email to an Outlook data file.
Permanent Resolution
N/A
Additional Information
N/A
Contact and Support
For additional information, please contact the IT Service Desk at 770-822-8915.