Some time back, when I was running Marcrium Reflect, I got an error saying the MFT was corrupt. Not immediately knowing what was the issue, I started searching on the internet. It came down to running the command chkdsk c: /r to recover/repair bad entries in the MFT table.
However, you can't run it when Windows is up and running so you have to tell chkdsk to run the next time the PC boots up by answering Y on the question asked.
Next boot time I saw the message that chkdsk would start running unless the escape key was pressed within a certain amount of time, which I did not do.
chkdsk started and it took about 2 minutes to finish the check and excuting the repair. After that, I could run Macrium Reflect again, taking my next snapshot of my harddisk.