Do you want to access the OneDrive folder or File System folder?
The “400” error told that the request is a Bad request.
If you want to access the OneDrive folder, please use OneDrive account rather than File System, because the File System could not have access to OneDrive Folder.
If you want to access the local machine folder, I have made a test on my side and don’t have the issue that you mentioned.
The flow works successfully as below:
Please check if you have created a proper connection to File system. Besides, check if you have chosen proper folder in Folder property of “When one or more files are added or modified (metadata only)” trigger.
Community Support Team _ Kris Dai If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.