Working on a datamat, and earlier this morning needed to make one small change which was to change a column name, hit save and it failed during the load and gave me the error "Unable to open the datamart because it is not connected to it's dataset. Wait a few seconds, and then try again." It ended up taking 5 hours before I was able to open it again for it to then fail after i did a different change which was changing a column type. Now it is locked.
So during that 5 hours i created a datamart with the same data... And sure as can be it also locked up with the same issue. I know i saw a post a few months ago that this was getting fixed but obviously not the case.