Huge Excel Log File on Mac

I am using Excel ver: 16.42 with Microsoft 365 subscription on MacOS High Sierra. Recently I was analysing my hard disk space and noted that Excel's log file occupied almost 15-16 GB. It was located in /Users/____/Library/Containers/ folder.

I closed excel and deleted the .log file and restarted my Mac. After reopening Excel, the log files got created again and it started expanding and reached 9 GB in a day! What is creating such a huge log file and how do I stop it?


Hi All - thanks for your feedback and information about this issue. It has helped us track down the root cause of the problem.

We have identified a code defect in excel 16.42 that would cause diagnostic logging to be enabled unexpectedly.  These log files are safe to delete. They're only meant to be enabled manually when someone wants to troubleshoot an issue with Microsoft support.

We've been able to disable the code defect by changing a setting in the M365 service, which should take effect on your computer simply by restarting Excel, possibly twice.  This should be sufficient to prevent any additional files from being created. You'll still want to delete any large log files that already have been created. 

The next update of Excel, 16.43, will automatically delete any of these leftover files in case you haven't already deleted them.

Please accept our apologies for the inconvenience and a sincere thank you for helping us find the cause.

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Question Info

Last updated November 19, 2020 Views 2,731 Applies to: