It's far more likely this was coincidental than an actual cause. I have
tested this by changing screen resolution on two different computers. I
first manually created a restore point, then changed my screen resolution,
in both cases outside the suggested specs of the monitor and had no problems
with System Restore taking either system back.
The usual cause of System Restore not being able to function is that its
file store is corrupted. Unless your system crashed when you changed
resolution, it's unlikely changing screen resolution would cause this
though, if you had tried to change resolution outside the specs of those
supported by your card, it's possible that would have produced an "Unable to
Restore" notice. But simply changing resolution in and of itself should not
cause this problem. Have you tried to reproduce this on your current
system, have you tried on any other system. As stated above, unless you
were trying to go outside the specs supported by your card or your system
crashed when you attempted to change resolution, it's more likely this was
coincidental and far more probable the SR file store located under System
Volume Information was corrupted.
The fix for that is to turn off System Restore, reboot and turn it back on.
If you are still having problems with SR, I suggest you do exactly that,
then test by creating a manual restore point to be sure it's working, if all
goes well, create another manual restore point, change screen resolution and
try it again. To turn off System Restore, open Control Panel, open System,
go to the System Restore tab, place a check next to "Turn off System Restore
on all drives," reboot, turn it back on, reboot again, then start testing.
