Parallels Support Team may ask you to upload files for further issue investigation, from screenshots and video recordings to core or memory dumps, or even a virtual machine.
Depending on the file size, use one of the following instructions below.
NOTE: Always compress file(s) to an archive. You may do that using native macOS functionality (Control+ mouse click/right-click > Compress), or using the Archive tool from Parallels Toolbox.
Before uploading files, Parallels Support will share a destination directory. Please follow the on-screen instructions to complete the procedure.
Once it's finished, please update Parallels Support so they can start analyzing the provided data.