Having same issue on 2019.3.0f6

Same problem in 2019.3.0f5.
Assertion failed on expression: 'gForceReimports->empty()'
UnityEditorInternal.InternalEditorUtility:ProjectWindowDrag(HierarchyProperty, Boolean)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

I get this with the function of PrefabUtility.
PrefabUtility.SaveAsPrefabAssetAndConnect(target, prefabPath, InteractionMode.AutomatedAction, out success);

If this happens, the sub-assets will not be saved correctly and the links will be broken.
I want a quick response.

I have the same issue with 2019.3.0f1 :

Assertion failed on expression: 'gForceReimports->empty()'
UnityEditorInternal.InternalEditorUtility:ProjectWindowDrag(HierarchyProperty, Boolean)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

Having the same issue on 2019.3.0f1

I can't edit my previous comment, but this issue was resolved by
- going to tools > Doozy > refresh for Doozy UI
- completely removing FMOD Unity Integration 2.00.06

Both are plugins that are installed in a 'base' unity project which we clone from when making a new project repository. The FMOD plugin seems to be biggest headache at the minute, they recommend downgrading to 2.00.05 for now.

Threads:
https://qa.fmod.com/t/downgrade-to-previous-fmod-version/15269
https://qa.fmod.com/t/lag-every-5-seconds/15241/4

Same issue here in 2019.3.0f1 Personal - project is based on a new Unity Lightweight Render Pipeline project and includes Unity IAP, Ads, Google Play Services, etc.

Anytime you try to make a new root folder in 'Assets', the following error appears in the console and no folder is made:

` Assertion failed on expression: 'gForceReimports->empty()'
UnityEditor.AssetDatabase:ImportAsset(String)
` FMODUnity.EventManager:CopyToStreamingAssets() (at Assets/Plugins/FMOD/src/Editor/EventManager.cs:534)
` FMODUnity.EventManager:RefreshBanks() (at Assets/Plugins/FMOD/src/Editor/EventManager.cs:37)
` FMODUnity.EventManager:Update() (at Assets/Plugins/FMOD/src/Editor/EventManager.cs:670)
` UnityEditor.EditorApplication:Internal_CallUpdateFunctions()

Fixed for me by upgrading project (from Unity 2019.3.0b10) to Unity 2019.3.0f1.

Still occur on 2019.3.0b12 (project upgraded from previous 2019.3 versions)

Same problem with 2020.1.0a11 Personal.

Also have this error on Unity 2019.3.0b11 Personal.

The full Error message is :

Assertion failed on expression: 'gForceReimports->empty()'
UnityEditor.AssetDatabase:Refresh()
SyntaxTree.VisualStudio.Unity.Bridge.<>c:<Refresh>b__11_0()
SyntaxTree.VisualStudio.Unity.Bridge.<>c__DisplayClass40_0:<RunOnceOnUpdate>b__0()
UnityEditor.EditorApplication:Internal_CallUpdateFunctions()