Been using Teamviewer for years, have occasionally had this problem but been too busy to investigate further but this time decided to try and work out why this is happening.
As I have tried to move a Directory on a Data Drive (not OS Drive) to a different subfolder, Windows reports that it is in use, upon investigation using Resource Monitor it shows that Teamviewer is reading and sometime writing to files within the Data Drive, not just talking one or two processes but 10+ at times, I am not doing any file transfer to the PC using Teamviewer so why would Teamviewer be accessing those files ?