I have moved my QGIS Project to a new Directory. On opening the project in new folder, Handle Bad Layer window pops up with a list of shp and csv files. I am able to correct the shp files using browse button but browse button is disabled when I am trying to provide the new path for csv files.
You needn't go into the .qgz file. Although there is no browse button, you can edit the file path in the "Datasource" field of the "Handle Unavailable Layers" window that pops up when you first open the project in QGIS. Click "Apply Changes" after the edit and if the window or line disappears, then the new path is working fine.