Outlook Office 365 cached mode crashing

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Len Raphael

Senior Member
Outlook version
Outlook 2016 64 bit
Email Account
Office 365 Exchange
Going on week 4 now where one user, me, can't use cached mode on one particular mailbox, without crashing OL. Works fine in non-cached mode. Mailbox size is well under the lowest recommended MS limit, especially after we got online archiving policy to apply correctly. (don't know if that's significant clue: but normal ways including powershell of applying retention policies failed on the inbox and sent folder of the problematic mailbox. Had to manually set the client level policy property to the specific policy instead of to the "parent policy" for the correct archiving to work properly.)

No obvious pattern. Safe mode doesn't stop the crashing. Repair, short or long, makes no difference. New profiles will delay the crashing for anywhere frrom an hour to several days, and then crashing resumes.

Completely clean install of Windows 10, omitting any antivirus app same problem.

Office 365 techs (lost count how many have tried and failed to find the cause despite running maybe half dozen tools and logging everything.

Every few days i have my appt with tier 2 MS support which lasts an hour and only eliminates dead ends. Have run at least 4 or 5 reset switches also.

Is there a way to shortcut this troubleshooting? eg. online archive an additional year, and then export the mailbox to a pst. Delete in the cloud and re-import? Would that filter out problematic objects?

Len Raphael
Oakland CA
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