>>Our main app seems to be fine, but whenever someone adds a task or a comment to our simpler "small" inhouse app, everybody's inhouse app hangs up.
>The installer I had used was ver 26054. I applied the 26085 snapshot this morning, before everyone came in, to try again.
>I inserted a new record - all fine. My colleague insert a record - freeze.
>Everyone now arriving, so had to revert server to 2.1.3 again.

I have just tested again with the released version of 2.5, and horray, I got an error message! Maybe I can get somewhere now ;-)

The error message is: Database is probably already opened by another engine instance in another windows session

My connection string is

server:c:\path\DBName.fdb

I noticed the case wasn't the same on all of them, so I changed that, and tested again. I am now back to the system freezing up again when 2 records containing blobs are inserted by 2 different users.

Once again, everyone is arriving, so I have reverted back to 2.1.3 again. I think I am going to have to set up a dummy test server, so I have more time for testing.

If anyone has any ideas of what to look at, please shout ;-)