1) Does this happen for *any* two-or-more invoices that you select in the invoicing list?

2) Can I assume that you're getting this error as soon as the Post Invoices & Credit Notes form is opened (as opposed to when you're clikcing the Post or Post All button)?

Hi Chris

This is happening to different people and they have their own way of doing it. However, as far as I can see you assumed correctly. 

What are your thoughts?

Hi Chris

This is happening to different people and they have their own way of doing it. However, as far as I can see you assumed correctly. 

What are your thoughts?

Not sure really, except to say that in normal processing it shouldn't be happening.

I can replicate the error by creating a conflicting entry in the SYSActiveLock table and then running the form. Exactly the same error as in your screen shot below. But I'll only get that if at least one of the Invoices that I've selected to go into the form conflicts with the lock that's already in place.

What I'd do just as a sanity check is to get everyone out of Sage 200 (and this means anyone connecting through any external 3rd party stuff you might have) and then - when you're 100% sure that eveyone's out - go into the database and clear out anything that might be left in the SYSActiveLock table.

(As an aside : the error handling in that form is really shonky. In that there isn't any. Even if there is a problem with a lock, you shouldn't be getting an unhandled exception - the typed exception should be getting caught and presented to the end user properly)