error nameplace isValid does not exist

[ChinoFurro]

Assets\USharpVideo\Scripts\USharpVideoPlayer.cs(1484,21): error CS0234: The type or namespace name 'IsValid' does not exist in the namespace 'Utilities' (are you missing an assembly reference?)

Assets\USharpVideo\Scripts\USharpVideoPlayer.cs(1505,18): error CS0234: The type or namespace name 'IsValid' does not exist in the namespace 'Utilities' (are you missing an assembly reference?)

Assets\USharpVideo\Scripts\USharpVideoPlayer.cs(1527,18): error CS0234: The type or namespace name 'IsValid' does not exist in the namespace 'Utilities' (are you missing an assembly reference?)

Assets\USharpVideo\Scripts\USharpVideoPlayer.cs(1559,21): error CS0234: The type or namespace name 'IsValid' does not exist in the namespace 'Utilities' (are you missing an assembly reference?)

[MerlinVR]

This is usually due to Unity corrupting the SDK, try following the steps at https://docs.vrchat.com/docs/migrating-from-2018-lts-to-2019-lts#empty-control-panel-or-missing-vrcurlinputfield. If that does not work, uninstall the VRCSDK, U#, and U# Video, then reinstall them.

[Ffuifffghbfssdkkc]

i followed these exact steps a few times but it dosent clear the errors. creating a new project works but i cant seem to clear these errors on my world and ive spent like 8hrs or something trying to do so

[MerlinVR]

Uninstall ShaderGraph

[KazyEXE]

Uninstall ShaderGraph

I just want to say thank you you've saved me so much time