Open B and C, and reference Level A (Drag A into their Levels Panel).
Open A, and place some Actors.
Save everything, and Restart the Editor (Important)
Open A First (Important), and try Deleting, Renaming, Cutting any Actors inside.
Editor will now be stuck “Updating Asset References” requiring Process Termination.
Try included project for quick demo.
Opening B or C before A will hide the bug. Preloading all Referring Levels before Editing the Referenced Level is not a practical option in a larger project. Deleting B or C will hide the bug. It takes minimum 2 references. The files are fresh and have no debris or orphaned garbage from previous bugs. The “Reference Viewer” looks correct.
Here is a quick workaround for avoiding the new 4.18 Editor Freeze with “Updating References” when editing Levels that are referenced by 2 other Levels, Sequences or other assets.
Instead of Deleting an Actor and triggering the Freeze, you can quickly drag it into any Sequence, “Convert to Spawnable”, and delete it there! This uses one Bug to avoid another Bug. The new Soft/Cross Level Reference enforcement system in 4.18 is broken. It is triggered every time you Delete, Rename or Cut an Actor in a Level that is referenced by 2 other external assets. It is triggered even if you abort the dialog about reference updates, leading to an Editor Freeze and requiring a Force Close and lost work. The new trigger is supposed to update the external Soft References to the new name or deletion, but instead hangs when it encounters 2 of them. However, the Sequencer “Convert to Spawnable” has not yet implemented this trigger when it removes the actor, which is finally a useful bug!
Unfortunately, for Renaming the Actors, you have to resort to much slower Renaming the Referenced Level so it temporarily escapes this broken new system. You have to be careful Not to Save all the assets that will now get dirtied and updated with the new Level name. After your edits, you can save the edited Level, and be sure to use “Fix up Redirectors in Folder” in its folder, because there is a hidden link asset there now with the old name, and this will remove it. Then, you can rename it back to the old name. You can either Restart the Editor, or Asset Actions/Reload to restore all the dirtied assets from the temporary name.
It’s all a big colossal mess, but such seems to be the future of Unreal development while a better engine comes along…
The reason I am stressing that point is because your coworker Q missed that note, and mistakenly suggested that he fixed the problem without Restarting the Editor. Then he abruptly left the conversation.
Here is that report with the same bug triggered from 2 Sequence references. In that case the problem is even worse, because the references cannot even be removed because of yet another bug, the Sequencer accumulating deleted garbage, even in completely emptied files.
These should all be debugging clues to the developers if they want to solve the worst issue, the Editor Freeze, which I am sure will show up for more and more people in time.
After following the repro steps I noticed that sometimes even with opening/loading levels B and C the bug was still present without restarting the Editor. This issue is being worked on. Please let us know if you have any more questions.
Hopefully, that was it, and the accumulating orphaned references from the older Sequencer files is not significant. I also see that specific bug report has been reopened after relaying my notes about the hex editor view.
Thank you again for truly resolving this problem. It is very refreshing to work with someone who gets things done!