Which Entities, Entries or associations were causing this I don't know but reversion to an earlier C5 database backup resolved the issue and I can add an Express Detail block again.

The database (prior to reversion) seemed to be sound with the exception of a number of old entity associations still being present after the entities had been deleted. However, deleting these alone didn't resolve the problem and so my guess is there were other database record remnants that were causing the block problems in listing available entities in the block add/edit dialogue.

It may not have helped that the new entities I'd created had the same handles as those deleted.

Nevertheless the system's robustness gives me concern before I crash on and create scores of entries.

I see from GitHub that 8.1 development addressed some issue in relation to the deletion of associations so perhaps that will sort this issue. I just though I'd post this in case it helps.

If I'm correct (and I'm probably not) knowing which tables may contain the records causing the problem would be useful. At least then I could go in and delete the erroneous records.

Anyone?

I have had the same problem. Cant be sure if i could repeat this but essentially I tried to delete an express object but couldn't. When editing it wouldnt show the save delete bar at the bottom of the page although other objects did.

So I took out a line in the ExpressEntities table in the database,

All seemed ok for a while but then later some Express objects got deleted for the database but I didn't know how.

After this I could no longer add Express detail blocks to any page. Just left with the spinning icon in the top right.

Cheers for the hint, I restored the database to an earlier version , remaded all my express objects and all is working now,

Feel this all started from some error that stopped me deleting the original express object so don't feel its all user error but some problem with the code exists.

I had to add the following to the TreeNodes table. (see the attachment)