All windows lose focus after 3-5 seconds

In Cox Backup, uncheck "Show status in menu bar". My issues went away without uninstalling Cox Backup.

I just want to report another culprit for loosing focus on windows under X11 (under Mavericks):

In my case it was iCloud foto sync. I had it deactivated in the iCloud Preferences panel, but anyway in the subordinated Options dialog the checkmarks for foto streaming and sharing were marked. I unchecked them, and now the focus stays on the window I use. Strange…

Hope it helps somebody… (it was difficult to find out; Foto syncing appearing in activity monitor gave me the clue)

Cheers - Klaus

Thank you for the python code!

After running it in terminal, I was able to find the culprit by selecting each active app one at a time and doing things in the app while waiting for the window to lose focus. Once it lost focus I waited until the python code identified the front-most app.

For me it turned out to be the latest version of MalTagsHelper - a plug-in for Mail.

Thanks iMichael -

Your script verified the same app for me as well (corporate Symantec software - I can't uninstall it).

Losing focus every 5 seconds as I type this....

Thanks for the code - will try that if my problem continues.

On two systems I was having this sort of issue but only intermittently.

In both cases I had trackball software installed for trackballs which are no longer in use because the hardware stopped working.

I have been using multi-button trackballs since the Mac SE - and find them far superior to any mouse - the trouble is that over the years the device drivers have often lagged behind and older hardware has dropped out of support. I have had a couple devices last for many years - but they have all failed to the point where now I have an external Apple Trackpad linked to each of my notebooks - but I had forgotten to remove the software that was necessary for the trackballs. One one machine I still have Kensington's MouseWorks installed and on the other SteerMouse - SteerMouse was awesome and filled the gap left by Kensington in their product support very nicely.

Will have to see over the next week or so if removing those no longer needed bits of software has solved my issue or if I need to use the code to identify other culprits.

Update - had one instance of lost focus during a period when the script was not running (changed the parameters to have it run longer).

So far only had one thing pop up unexpectedly - Google Drive - though I did not notice a loss of focus at that time as I may have been clicking from one app to another at the same time.

I am turning off Google Drive for awhile to see what happens, that was only on one of my two systems.

I am thinking about a modification to the code where instead of showing output every tick comparing the new value to the old value and then only showing output when there is a change of focus - that way it could run for much longer and have a smaller output that is easier to see what happens - of course then it might be harder to detect an unwanted change since most entries would be alone - whereas an unexpected loss of focus while in a given app would be only one or maybe two outputs amidst a large block of whatever you were working on when it happened.

On my work system at least I switch between many apps in the course of doing my work - at home I do run lots of apps but don't need to switch between them nearly as often.

Thank you really much!

I know it is about a year later, but I just had this same problem with Cuda_Drive!

After using the python script to detect (see accepted answer), I was able to confirm that Google Drive was causing this problem.

Thank you for this tip. It worked for me as well.