Hi @benoitfl. There was a previous report of this error here (interestingly, also by a Teensy user):
You can try the solution shared by weshowe:
To be more specific, the solution they found was to close all Arduino IDE windows and then delete all the files and subfolders in the folder at the following path:
C:\Users\<username>\AppData\Local\Temp\
(where <username> is your Windows username)
Please be very careful when deleting things from your computer. When in doubt, back up!
If looking for it with your file browser or command line, note that the Appdata folder is hidden by default. On Windows "File Explorer", you can make it visible by opening the "View" menu, then checking the box next to "☐ Hidden items".
You will find that some files or folders can't be deleted because they are in use by some process that is running on your computer. Just skip those. The idea is only to clear out some of the accumulation of temporary files. If some are still left behind in the folder, no problem.