File drag & drop from Windows Explorer not working in Godot 4.5.1 .NET (Mono) editor

[Crayon-Powerking]

Tested versions

Godot 4.5.1 (Mono/.NET, Windows 64-bit)

System information

Vulkan 1.4.312 - Forward+ - Using Device #0: NVIDIA - NVIDIA GeForce RTX 4060 Laptop GPU -12th Gen Intel(R) Core(TM) i7-12650H (2.30 GHz)

Issue description

When using the .NET (Mono) version of Godot 4.5.1 on Windows,
I cannot drag and drop any external files (e.g., PNG, WAV, etc.)
from Windows File Explorer into the FileSystem dock of the editor.

The cursor shows a red “no” symbol, and the file is not imported.

However, using the standard (non-.NET) version of Godot 4.5.1 works normally —
drag & drop behaves as expected.

So this issue only affects the Mono/.NET builds on Windows.

Steps to reproduce

Download and launch Godot 4.5.1 .NET (Mono) version for Windows.

Create or open any project.

Open the FileSystem dock.

Try to drag a .png file from File Explorer into the dock.

Observe: cursor turns red “no” symbol, file not imported.

Try same steps in standard Godot 4.5.1 — works normally.

Minimal reproduction project (MRP)

[MiracleAig]

I tried the same thing on windows and something I noticed is that if you try and drag images that synced to one drive in the cloud but are not on your device you will get an error importing that image. However, when I did this with an image that was on my device it worked without issue, so perhaps your problem is trying to import images that are not currently on your device. To fix it try starting OneDrive on your computer and see if that changes anything.

Images that are synced to the cloud but are not on your device look like this (on the right) while images on your device look like this (on the left). However, if this wasn't your issue I wasn't able to reproduce the problem to your specifications. If you could upload a video of you trying to reproduce the issue would help.

The files with an X are the ones that were synced to OneDrive but not on my machiene.

[Crayon-Powerking]

It's not this kind of red error. Instead, when dragging it in, a prohibition symbol will appear, similar to when you import an incorrect file. You can only drag it in under the file path of that file, and that error cannot be captured using screenshots on the computer. Maybe taking a photo with my phone would work, but I no longer use the .net version.