This is usually due to having added images to Zotero notes before they were officially supported in Zotero 6.
The 64-bit version of the Zotero 7 beta might avoid the out-of-memory error and give you a proper error pointing to the note in question, but you can also search for data:image in All Fields & Tags mode to in the library root to find notes with pre–Zotero 6 images and remove them.
Report ID 414325781. And also D1063756919. So Zotero now opens; I 'see' the library I'm currently working in. But I cannot add a new 'report' to that collection AND I cannot sync (e.g. I added a new group , but I can't see it).
DELETE FROM itemDataValues WHERE valueID NOT IN (SELECT valueID FROM itemData)
Nothing to do with sync. A cleanup process at startup is taking a very long time for you. You can try waiting longer without doing anything, but it also looks like you have your data directory on an external or network share, which may be making things much slower. (Someone had the same problem the other day. And moving the data directory back after resolving this was likely only a temporary fix, since this query — which should take a fraction of a second, but was taking vastly longer for you and them — only needs to run occasionally.)
Upgrade Storage
The 64-bit version of the Zotero 7 beta might avoid the out-of-memory error and give you a proper error pointing to the note in question, but you can also search for
data:imagein All Fields & Tags mode to in the library root to find notes with pre–Zotero 6 images and remove them.Can you provide a Debug ID for reproducing this?
So Zotero now opens; I 'see' the library I'm currently working in. But I cannot add a new 'report' to that collection AND I cannot sync (e.g. I added a new group , but I can't see it).