I would not recommend using the Pause While in this way because it will prevent all other actions from running while it is paused.
Also, there is a way to use Pause While, with a timeout.
Parameter "timeout" = "{now}"
pause while { ( now-parameter "timeout" as time ) < 1 * hour AND exists running applications "chrome.exe" }
I haven’t tested this relevance for syntax, but the idea is solid and I use it all the time, but usually for a time out of 5 min or less. I definitely would not use it for more than 1 hour.
A better method is to add this relevance to the Fixlet/Task relevance itself and have it as an open action targeting a group of computers. Then the Fixlet/Task will only run when the programs are closed.
The method I recommend for updating endpoints is to have a baseline with a bunch of stuff in it that should target all computers, or nearly all computers. This baseline contains all of the software that should be installed and updated. You target this baseline to only run when no user is logged in.
Separately from this baseline, you have actions that target all endpoints that already have the software you are updating installed, and only if that software is not running. This will update more likely than the baseline, but in a different way.
Separately from that you can have yet another action that prompts the user to save their work because it is going to close the running application and update it. The trick is you set this action to start 2 weeks in the future so that the majority of your users will never see it and be updated by the above actions.
The next thing to do is have an open action that runs forever and prompts all users to reboot their computers at least once every 14 days give or take. If they haven’t rebooted, then this will force them to.
Tell your users if they don’t want to be bugged by this, then they should reboot their computer at least once a week at the end of the day and just walk away and let the updates roll. WU/WSUS should take care of some of the reboots as well.