Problem making Acer Aspire recovery disks

After helping my daughter to set up a new Acer Aspire Timeline laptop, I left when the recovery DVDs were in the process of being burned. I had an anxious phone message later to say that the last (4th) disk had been completed and ejected but that the software remained unremovable on the screen - could not be closed. The laptop had to be shut down via Windows Task Manager. It restarted OK. The question is, can I be sure that the final recovery disk has been closed properly or have I got to go through the process again to make sure - it takes ages.
Has anyone experienced this before, please?
Steve