I click on the clip, say 'open in trimmer' - go to insert marker, type in the name that I want to use, click on 'save' icon - have done this many, many times to label clips so that the name is attached to the clip.
This time however, Error message said - "access denied, check to see if read only file or if being used by another program'
I could not label any more clips - this happened on all other clips about halfway through the process.
I had labeled several clips successfully up to this point in this project - and have used this process extensively before in many other projects with no problems.