Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Which one should I do first in Windows 7? Scan Disk or Defragmenter?

share|improve this question
up vote 3 down vote accepted

Scan disk first, as defrag will fail if it hits a bad block. Actually, I am pretty sure defrag does a scan disk first to make sure there are no issues before proceeding, but it is still the same sequence.

share|improve this answer
Yeah, I think the old defrag unnder Windows 95 would ask you to run scandisk first. – surfasb Nov 10 '11 at 4:24
So if we scan disk then defrag we end up scanning twice since defrag rescans the disk? – Pacerier Aug 7 '13 at 13:28

Many of the defraggers will not defrag a "dirty" disk, as it would be incorrect to try and defrag a disk that is "dirty". Dirty means that it stopped (was stopped) without finishing something. You (or the program(s) should always check the disk first before defragging.

If you are having disk "problems" it might be very unwise to defrag it at all. if your having disk problems because of memory issues, it can be bad to checkdisk or defrag :-). If the problems that the disk is having are not just a Crash, and a cleanup from the crash, you should address any disk or memory issues before doing either. If it is just a crash, then no problem.

share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .