I have a Windows 10 machine that with Microsoft 365 installed. MS Access is throwing an error every time I attempt to open a .accdr file. If I change it to .accdb there is no problem. I am not able to replicate the issue on other machines. I have done a re-install of M365. Any thoughts on possible fixes?

Seen this once before, few years ago now.
Got round it by going through Trust Center Settings in Access.
Trusted locations should have directory where file is located, then macro settings and select enable all

This may help as well.

https://answers.microsoft.com/en-us/msoffice/forum/all/access-2016-wont-open-accdr-file-microsoft-access/e9bc5d8c-ba0d-48d1-bf36-44c2e7f4d7e0

1 Spice up