Outlook not responding issues

[tek9]

Hi all.
Hoping someone can give me some ideas on how to troubleshoot this issue.
Basically I have a client that's complaining for a while that his Outlook program freezes a few times a day, at random, with the usual (Not Responding) message in the title bar. This is what he has:
Lenovo ThinkCentre M710, core i5-7400, 8GB RAM, Crucial MX500 500GB SSD.
Latest version of Office365 desktop apps, latest version of Windows 10, using O365 Exchange P2 for his email. He has 3 Exchange Online accounts configured in his profile. One is tiny, barely used, the other 2 are large, around 18GB each, but he only uses one account for his work, the other is just for referencing another user's email.
He's been complaining for a while that when he would click into certain email threads (usually this happens for very long threads, but it can also happen for short ones at random), with the Preview pane enabled, Outlook would not respond anywhere from a few seconds up to a minute-and-a-half. I tried updating everything, no difference. If I turned off the Preview Pane, it would help until he would open the offending email, at which point it would freeze. Switching Conversation View on and off didn't make a difference.
Tried switching his HDD to an SSD made the computer faster but didn't help for this issue.
Even with all programs closed and just Outlook open, it would be the same.
Outlook add-ins are disabled, except for those that usually come with Exchange Online.
Task Manager shows the CPU spiking to 100% for the duration of the freeze, then goes back to normal when it "defrosts".
Other than this Outlook issue, just with certain emails, the computer is very snappy.
Any ideas what to look for now?
Thanks.

 

[Sky-Knight]

You've done all the usual things, the next step is to obliterate the Outlook Profile and rebuild it.

 

[Mick]

Have a look with Process Monitor (or Process Lasso) and see if you can work out what's causing the CPU thrash - may be some clue there.

 

[nlinecomputers]

Event logs may have a clue as well. A COM add in may be hanging, causing outlook to wait until the add in finally crashes allowing Outlook to continue.

 

[HCHTech]

36GB of email is pretty large, as well - I would look into archiving some of that if possible.

 

[YeOldeStonecat]

Even though modern versions of Outlook support connecting to multiple mailboxes within the same profile....(so you see all 3 mailboxes at once on the left pane)....I've just notice it can get cranky with that.

Honestly...18 gigs...36 gigs..shouldn't bog down Outlook on a rig of that spec. I have tons and tons of clients with huge inboxes...20, 30, 40...no problem. Now, if you have some old pentium D or celery rig with just 4 gigs and a rotating spindle drive and intrusive antivirus...yes Outlook with a large mailbox will gag. But that's not Outlooks fault. It's the end user for trying to run a large database on a computer with inadequate specs to do the job reasonably.

Any fairly modern rig with an Intel i5 or higher (or equiv like todays new Ryzens), 8 gigs, and an SSD...Outlook with a huge mailbox should run like a champ.

So..let's revisit those 3 mailboxes. How are they being used? Can some be replaced with shared mailboxes?

 

[tek9]

One mailbox is his primary one that he uses constantly. The other large one is another employee's mailbox that he monitors from time time (I think there are 4 people with that particular mailbox in their Outlook profiles), as is the third, small mailbox. Outlook is freezing constantly when he's using his own mailbox, even if he doesn't switch between the different mailboxes.
I'm going to login now and use process monitor and eventvwr to see if they'd shed some light. Really don't want to start a new profile and re-download 40GBs of data. Though they do have a dedicated 150MB fiber line....

 

[Sky-Knight]

Every time I add or remove a mailbox to a user, doesn't matter if it's full or shared there's a small chance the Outlook profile goes out of whack, and Outlook does strange things.

I know you don't want to reset that profile, but seriously... it's the easy fix.

 

[YeOldeStonecat]

Try blowing out the 3x OST files.
Close Outlook...give it a few seconds to fully close in the background, browse to the hidden folder within %userprofile%\appdata\local\microsoft\outlook and delete the 3x OST files.
Open Outlook...it'll rebuild those 3x OST files.

No data is lost when you blow away OST files. You can safely delete those all day long. They're just local copies of the mailbox so Outlook can browse faster.
It'll quickly rebuild within a half hour...less even if on a 150 meg pipe.

Sometimes those can get wonky, very safe to delete and let rebuild.

 

[tek9]

Updating you guys after all this:
I tried basically everything over the past few weeks and nothing helped.
First I removed the Outlook files and let it redownload. No difference. Tried a different Outlook Profile, same thing. Tried to use ProcMon and ProcessLasso but nothing was showing up out of the ordinary when the freezing occurred. The only third party add on installed is from Teamviewer but that's disabled. I also deleted the Outlook folder from the Teamviewer program folder but it didn't make a difference.
So yesterday I created a new user account on the computer, copied over his files, created a new Outlook profile etc. He just called me that it was freezing again!

(BTW there is another user in the office that has these large email accounts loaded on his Outlook with no issues, so it's not that.)
I don't think there's much left for me to do here. The next thing I'm planning is a nuke and pave unless someone here has a better idea.
Any input would be welcome.
Thank you.

 

[Moltuae]

Does the account have any mail rules set? Lots of rules (or badly configured rules) can cause Outlook to hang.

 

[AlexCa]

He's been complaining for a while that when he would click into certain email threads (usually this happens for very long threads, but it can also happen for short ones at random), with the Preview pane enabled, Outlook would not respond anywhere from a few seconds up to a minute-and-a-half. I tried updating everything, no difference. If I turned off the Preview Pane, it would help until he would open the offending email, at which point it would freeze. Switching Conversation View on and off didn't make a difference.

Maybe there's something in common in those emails? Like hyperlinks that don't go nowhere (I've seen that causing similar problems), or maybe it's Antivirus interference while scanning hyperlinks in those emails. Try to disable the AV and see if it makes any difference.

 

[tek9]

None of the big email accounts have any rules whatsoever. The tiny mailbox has one basic rule to move messages from a particular sender into the Inbox.

 

[tek9]

Maybe there's something in common in those emails? Like hyperlinks that don't go nowhere (I've seen that causing similar problems), or maybe it's Antivirus interference while scanning hyperlinks in those emails. Try to disable the AV and see if it makes any difference.

There doesn't seem to be a common denominator anywhere. They're only using the Windows 10 built in Defender A/V.
Everything is identical across the two machines that have access to these email accounts, and one of them is acting perfectly fine.

 

[Kenosh]

What about a repair of MS Office