Dear AccessVandal
Good day! Thank you for posting in Microsoft Community. We are happy to help you.
Based on your description, it seems that your Access 365 always automatically create a Backup database file.
If my understanding is correct, this behavior could happen if Access crashed, and it attempted to recover. In this scenario, please try to use online repair tool to repair your Access then check the behavior: Repair an Office application (microsoft.com)
Besides, it can also happen if you Compacted/Repair the database. Perhaps manually or if you are using the Compact on Close option (which should be avoided). If so, please turn off Compact on Close option to see the behavior.
As you use Access, it will grow in size, to a certain extent, this is normal. When you Compact and Repair such space will be reclaimed.
As you mentioned, opening and closing will delete the backup file automatically. This is a normal behavior, For the cache file, it will save din the temp folder: %appdata% \Local\Microsoft\Office\UnsavedFiles, please go to this location to check if you can find a file in there to help us narrow down the behavior.
So, we would like to collect more detailed information about the situation you are experiencing so that we can have further investigation:
- Can you tell us how did you created the database file in Access?
- Please share the product information of Access with us so that we can do the same test on our end in the same environment. Please go to File>Account then shares the screenshot with us.
We’re looking forward to your reply and will continue to help you all the time! If there are any misunderstanding or unclear, you can post back in your free time.
Your understanding and patience will be highly appreciated. I hope that you are keeping safe and well!
Sincerely,
Stacey | Microsoft Community Moderator
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