UI The canvas gone after a refresh (5.4.0f1)

When i updated the project to Unity 5.3.5p7, I got this issue. Currently, I updated the project to Unity 5.4.0f1 and i still have this bug.

The steps how this happens:
0) Open unity editor.
1) Open any kind of application on your computer.
2) Back to unity editor.
3) Canvas (UI, GameObject) has gone.

Also i have short video:
https://i.gyazo.com/f36d2f77ae78513423a29854b1e5630f.gif

Case #814796.

 

This seems to be a known issue, I found an item in the issuetracker that sounds very similar.

UI images and texts disappear on editor focus change
https://issuetracker.unity3d.com/issues/ui-images-and-texts-disappear-on-editor-focus-change

 

Yes, we have the same issue. I reported, also i attached my project. I hope they'll will see this problem and will fix.

If people can vote on this it will be great to help us.

Thank you.

 

Hey, So yes this is a known issue, I thought we had a fix in 5.4 but apparently i was mistaken. I'll try and track it down see if it just got missed for 5.4 or if we truly hadn't fixed it.

 

Hey. Tautvydas from QA team answered me today in the morning, he has solved this problem by deleting Photon Unity Networking plugin.

Thank you very much for this amazing support.

 

Hey,

I took a look into the bug and managed to solve it.
When running into this bug, try to reimport the Plugins folder by right-clicking on it and choose 'Reimport'. This might regenerate some files which are causing the problem.

If this doesn't solve the problem, do the following steps:
1) In your project navigate to the Plugins folder
2) Look for a file named 'Photon3Unity3D.dll.mdb' (the filename extension is very important) and delete the file if it exists
3) Within the Plugins folder navigate to each PUN-related subfolder (Metro, Uwp) and
4) Look for 'Photon3Unity3D.dll.mdb' again and delete the file if it exists

 

Just to summarize, we actually do have a bug still open - it's related to duplicate asset names existing oddly enough. So like @ChristianSimon found, deleting duplicates of the same named files will do the trick.

Working on fixing it still, but it's a bit trickier to work out and no timeline set for the moment.