Hello Louise,
I've not experienced the same problem with Content Aware Removal, even working with complex, high resolution photos. Some processes in photo editing can be very intensive & require a stable PC environment equipped to cope.
Perhaps there is something about your PC set-up that is causing the issue.
If you could, please post a diagnostic report for your PC. Go to Start (Windows icon) and select "Run". Type "dxdiag" (without inverted commas). After completion, save the report as a text file and post here as an attachment.
PIX
PIX YouTube channel