Out of the thousands and thousands of values and strings in the registry, what makes you think THAT particular one is anything to be worried about and why in the world would you be performing maintenance in the registry anyhow. If you were knowledgeable enough to be making edits in the registry reliably, you would also be knowledgeable enough to know what that string was related to.
If you are using CCleaner or another utility, you're just rolling the dice. Those utilities are widely known to completely bork systems if the wrong entry is removed or changed. So long as you have both a good antivirus AND malware scanner installed and configured for real time scanning, along with running an occasional root kit scan, you shouldn't have much if anything to worry about.
SfTracingState is related to SuperFetch, and is an integral part of windows.