"could not save as "filename.tif" because the file is already in use or was left open by another..."

Lately(last month ish.) i get this error a lot when i edit pictures in photoshop. First i do the basic editing in LR, then i do the more advanced stuff in photoshop, and save the file, no problem.But if i want to change anything later and reopen the file in photoshop, about 50% of the time i get this error when i try to save it again. This is interrupting my workflow A LOT, as i have to create duplicates, and resync them into lightroom, making a new(2gb TIFF) file everytime i reopen a project in photoshop to make changes.Somebody please help!