Titanium Software's "OnyX"

As for Restart.app, that's going to require some digging. What the message is saying is that at some point in the past you mounted a disk image (xxx.dmg) that contained the file "Restart.app" and now Onyx wants to delete the .dmg file but cannot because "Restart.app" is showing as in use. I have no idea what restart.app is or does. It is NOT part of the operating system, AFAIK. There is no such thing on my system and a quick search failed to turn up anything useful on the Internet about it. I suspect it is part of something you installed. What caused you to think you needed to run Onyx? Are you having a problem?

You can try to find the app file with Spotlight, or if that fails you can try another search tool (Find Any File, EasyFind, etc), or you can search again for it manually. You can try to find the .dmg that is mounted in Finder. To do that, open finder and on the sidebar under "Devices" there may be a "drive" showing that isn't really a drive but the .dmg file. If it is there you can try ejecting it. If that doesn't work, you are going to have to find restart app in the Activity Monitor (under Utilities) and quit it from there. Finally, you can try to unmount the dmg drive in Disk Utility. Open DU, look for the mounted drives on the left side, find the one you think may have Restart.app on it and unmount it.

Bottom line, searching for restart.app is going to be a real pain. Good luck with it.

I came across this in my internet search (not google).

http://www.tensionsoftware.com/osx/macrestart/

Does it look like something you have downloaded previously?

Hi MacInWin it seems that after i trashed the 2014 onyx dmg file the restart.app did not appear.
I assume that this problem is solved - tried all kinds of searches including spotlight but no sign of restart.app.

Hopefully I will not have to search for it again.

The reason I thought I needed onyx was that (if you recall) i had problems with backups and spinning wheel etc, so a clean up program may fix the issues and speed up mac.
For now it seems all is ok.
Thanks for your thoughts.

Hi ferrar - thanks for the search, but I did not get anything from tension software at all.

Just waiting for this backup to finish to see if there any new problems.