UMG Asset Can't Be Opened if Animation Window is Closed.

Unfortunately I have no steps to reproduce this bug, but one of my UMG assets can no longer be opened. It displays correctly when playing the game, but can no longer be edited.

This seems to happen if you close the animation window in the UMG editor, then close and restart the editor with that same window configuration. At least, that’s the only plausible reason since nothing else has changed.

The problem is in WidgetBlueprintEditor.cpp - Line 680. Sequencer is NULL but it’s trying to dereference the pointer to it, creating the crash. (Surely this should be wrapped in an If statement??)

The previous entry in the callstack comes from lines 83 > 89, which is wrapped with the comment “If the user has closed the sequencer tab, this will not be initialized”. It’s obviously clear that the problem is because line 680 does not have the same check.

After some further probing it appears I can’t open ANY User Widget anymore, I’ve rest the UI layout for the engine, deleted all folders other than Content, Config and Source - and still it keeps crashing.

Rolling back and/or updating in Perforce also failed to work - which I figured it would since there were no file changes. Here’s an image…

Fixed it by resetting the UI Layout for the editor - However there is clearly an issue here.

Hello ,

This is a known issue. I have provided a link to the original thread below. You can visit that thread for future updates on this issue. Thank you for your time and information

Link: Assertion failed: IsValid() File:D:\BuildFarm - UI - Epic Developer Community Forums

Make it a great day