Most plugins broken: UI Theme is not a valid member of Studio "Studio"

Most of my installed plugins aren’t working now due to a strange bug with UI theme being a missing member.


This started when I downloaded and opened the place file contained in this devforum reply. It forced a studio update, closing my open studio windows. When studio had completed updating and opened that place file, I was getting the UI Theme not valid errors/warnings.

I reinstalled roblox from, but no dice. Then I deleted my User/AppData/Local/Roblox directory and did another install, still erroring.

As a backup; the placefile that caused this problem is here. I don’t recommend downloading it and opening it. GameNotWorking.rbxl (31.2 KB)

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I launched studio with user plugins disabled. UI Theme works fine on included Animation plugin

welp it’s been removed according to the version 477 changelog


A few plugins did have pending updates that resolved this. The rest must must just be a little late on the change.

I’ve uploaded a fixed version of the class conversion plugin using Studio.Theme instead

Sorry for the disruption wrt plugin breakage. We didn’t realize that many existing plugins rely on this - we are going to revert the removal of this property with a Studio patch tomorrow morning. Plugin authors are still encouraged to migrate to the new Theme API but existing plugins should start working again tomorrow.