TypeError: document.querySelector(...) is null" {file: "chrome://zotero/content/components/tag-selector/tag-list.js" line: 166}]
First, though it's unlikely to help, upgrade to Zotero 5.0.73. You still have 5.0.72.
Then check your database integrity from the Advanced → Files and Folders pane of the Zotero preferences.
Finally, if you're still having trouble, provide a Debug ID (different from a Report ID) for Zotero startup through the error, using the "Restart with Logging Enabled…" option.
Upgrade Storage
Then check your database integrity from the Advanced → Files and Folders pane of the Zotero preferences.
Finally, if you're still having trouble, provide a Debug ID (different from a Report ID) for Zotero startup through the error, using the "Restart with Logging Enabled…" option.