Data Storage Location
When using the custom data storage location (D:\ a1021\Documents\Zotera), Zotero starts with an exception error message and enters automatic update. But before today, Zotero was running normally. After restoring the default file location, Zotero's functionality returned to normal. So, there is any limitation on the Zotero's custom database location function?
https://s3.amazonaws.com/zotero.org/images/forums/u13988330/2iauf8jmvx18or0gl6vu.jpg
https://s3.amazonaws.com/zotero.org/images/forums/u13988330/2iauf8jmvx18or0gl6vu.jpg
Did you upgrade to Zotero 7 today?
Storing the database on a network share may be less likely to work in Zotero 7:
https://forums.zotero.org/discussion/comment/479899/#Comment_479899
(That was macOS, but whatever Firefox/SQLite changes led to this may apply to Windows as well.)
You can try the Zotero beta — which is based on an even newer Firefox version — to see if that's any different.
It's also possible this was just some change to your system/disk configuration. Network shares (and to a lesser extent external disks) are always less reliable than an internal disk for storing a database.
https://s3.amazonaws.com/zotero.org/images/forums/u13988330/jvckji3l9hrwwyaqgjo5.jpg