Error When Trying To Remove Web Application Transaction Monitor

Prelude…
Sometimes I find myself in situations which give me the ‘Duh!’ feeling, like doing something wrong and not being able to fix it at that moment. However, when trying to solve it a day later, it’s fixed in the matter of minutes while the day before the solution eluded me totally. And not only that, but when I solve it, I don’t feel that smart either since I know I stepped into a well known pitfall which I should have avoided…

For me these are signals it’s time for a break and gladly within a few weeks I’ll have a break of one whole week! Nice!

Issue
Got this error when I tried to delete a certain Web Application Transaction Monitor: The item you are trying to delete cannot be deleted because another object references it. The object must be deleted before this item can be deleted:

But at that moment I couldn’t crack it. Yes, there was a Distributed Application using this very same Monitor. So normally you remove that DA first (or modify that DA so it doesn’t use that particular Monitor anymore).

But also the DA kept throwing similar errors! And the cause of that eluded me. Instead of wasting valuable time, I exported the MP containing this Monitor and set it aside for another day. Simply because I already felt that I was missing something very obvious here…

Cause
As it turned out, that particular Monitor was used in a DA. But that DA had some other modifications as well, like newly added Dependency Monitors, in order to enable the rollup of the Performance, Security and Configuration parent monitors as well.

After having removed those Dependency Monitors, one by one, I could easily remove the DA containing that Monitor. And afterwards I could easily remove the Web Application Transaction Monitor.

Recap
Whenever the removal of any Web Application Monitor throws errors like item you are trying to delete cannot be deleted because another object references it. The object must be deleted before this item can be deleted, that Monitor is being used (referenced) in one ore more DAs.

When removing that DA throws the same error as well, changes are that you have some modifications on that DA as well.

So start with the removal at the bottom and work your way up. By removing all the references one by one, soon you’ll end at the Web Application Monitor involved and than you can remove that Monitor without any hassle.