Cannot open attachments in Outlook 2016
Solved Email & Outlook
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Dexter Morgan
January 29, 2019
2 replies
9,420 views
Reviewed by moderators

Double clicking attachments in Outlook 2016 either errors with cannot create file or opens nothing at all. Saving to desktop first then opening works. Every user wants a fix rather than the workaround.

Accepted Answer
Verified by Mariya Beckham, Forum Moderator ยท Reviewed January 2019

Cannot create file means the Outlook temp folder is full. Outlook keeps a copy of every opened attachment in a hidden cache and stops at 99 copies of the same filename.

1
Find the cache path in the registry under Outlook Security, value OutlookSecureTempFolder.
2
Open that path in Explorer and delete everything inside.
3
People who open the same report name daily hit this every few months. A small logon script that clears the folder ends the tickets for good.

2,400 cached files in that hidden folder. Cleared and everything opens. Logon script deployed. Solved.