If you restore from the backup, select the collection, go to Tools → Developer → Run JavaScript, and run ZoteroPane.getSelectedCollection().key, and tell us the result, we could say more.

[JavaScript Error: "Error(s) encountered during statement execution: database disk image is malformed [QUERY: SELECT data FROM syncCache WHERE libraryID=? AND key=? AND version=? AND syncObjectTypeID

[JavaScript Error: "The range cannot be deleted. [setText:y:\zotero\word-for-windows-integration\build\zoterowinwordintegration\field.cpp]"]

[JavaScript Error: "Component returned failure code: 0x804b000a (NS_ERROR_MALFORMED_URI) [nsIIOService.newURI]" {file: "chrome://zotero/content/xpcom/storage/webdav.js" line: 205}]

[JavaScript Error: "Request timed out"]

It seems like there's a navigation popup that automatically appears without JavaScript when the window becomes narrow, but JavaScript is required to make it functional, i.e., not a big empty white box

[JavaScript Error: "Object has been deleted. [importDocument:y:\zotero\word-for-windows-integration\build\zoterowinwordintegration\document.cpp]"]

[JavaScript Error: "invalid language tag: "en_US"" {file: "chrome://zotero/content/xpcom/data/itemFields.js" line: 477}]

[JavaScript Error: "Could not open the file at C:\Users\[…]\AppData\Local\Temp\Zotero\IFAIMKGB.tmp for writing: 0x807104C8"]

JavaScript error Could not open the file

[JavaScript Error: "Error: Error(s) encountered during statement execution: FOREIGN KEY constraint failed [QUERY: INSERT OR REPLACE INTO itemTags (itemID, tagID, type) VALUES (?, ?, ?)] [PARAMS: 21599

(Please start new threads for new issues — the thread you posted to isn't related. I've moved this to a new thread.) [JavaScript Error: "HTTP GET https://[…]@dav.jianguoyun.com/dav/zotero/QG3NRMBT.pro

I know there are plugins and I've also discovered how to do it with Javascript in the debug console, so I would hope it's not terribly difficult to implement, since the former approaches will desync w

[JavaScript Error: "uncaught exception: undefined"]

Zotero is mostly javascript. What we'd need is

Open Zotero's Javascript Console by going to Tools > Developer > Run Javascript.

[JavaScript Error: "OAuth request failed with undefined; response was undefined" {file: "chrome-extension://ekhagklcjbdpajgpjgmbionohlpdbjgc/zotero.js" line: 314}]

[JavaScript Error: "HTTP POST https://api.zotero.org/users/1285947/items/TUNHJZ3G/file failed with status code 400:

[JavaScript Error: "HTTP OPTIONS https://[…]:********@dav.jianguoyun.com/dav/zotero/ failed with status code 503:

[JavaScript Error: "translators is undefined" {file: "chrome://zotero/content/fileInterface.js" line: 565}]