How to find the cause of a hanging on start application?

Kubuntu 18.04
KDE Plasma 5.12.8
Frameworks: 5.44.0
QT 5.9.5
Kernel 4.15.0-58-generic

Ive experienced a few times lately apps hanging on start up. Hanging upwards of 10 min before they start.
I just experienced it again when I started Tor browser where it didnt start when clicked and about 10 min later it popped up. Ive also experienced it - though very rarely - opening another instance of Firefox and when starting libreoffice.

Ram is around 2gb of use with 10gb still to use and cpu is around 20% up and down.

Ive looked through the logs but nothing stands out to me as being “the” thing. How would I go about hunting down the cause?

Just a thought, but I experience a pause (not 10 minutes) of a minute or 2 on my slower laptop when Timeshift is taking the snap shot. I checked the time of the snapshot and it was at the time of the long pause.

Have you tried booting in recovery mode, to see if the problem shows there? If that doesn’t show up any thing then at least you’ll have another tick off what you have done. Also it is worth checking for any bugs on the Kubuntu site to see if it is listed there.

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No backups running. Also at times, no other apps running either.

I have been looking into the Kubuntu issues.
I have not found anything yet.
Certain apps do have a tendency to catch but
this seems more recent. I have this same setup
on my laptop with less ram and cpu and Ive not
seen the extensive stalling. FF is very rare, Tor
does it more, Libre, I use daily - is about 50/50
on doing it. Just strange.

I will try the recover mode next.

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You shouldn’t exclude a possible hardware issue, entirely.

… such as a hard drive? bad sector? Sounds familiar!

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:laughing:
:laughing:
…

Could be… but… wouldnt or shouldnt that affect other software.
Not just 3?
No other has/is/yet affected.
Im kinda thinking its just Tor and Libre maybe affecting FF but… that could be off.

Does not have to. About two years ago I was playing several games, sometimes one, sometimes the other and sometimes a third one. Only one of them was crashing, frequently, without obvious cause. Later, I found out that my CPU was not cooled well enough. It was enough for pretty much all games, except that single one.

Ill have to pay attention to temps and how long the unit has been on then to see if I can start seeing a pattern.

Thanks for pointing that out.

Have you used htop before starting the apps in questions you might find it helpful.

I have htop installed and I have it on now, I started one of the apps but Im not sure how this helps me.

It might show you that something is pegging your processor, excessive I/O or that you are out of available ram. One more thing, you may see something running when you execute one these programs that you don’t recognize and shouldn’t be running, like bitcoin mining.
If you don’t see any difference in these items then I am at a loss too.

ah, Ok. Got it.
Ill run it again when I dont have so many apps running and Im working so I can see everything.

Thanks.

That would be best, start fresh, don’t start any apps and take a snapshot of htop for reference. Then while watching htop start one of the apps that are problematic and see what is causing the hang.

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