Outlook desktop - remember expanded folders

[ErikJan]

I have folders (in my PST, but I see this for OST's as well) which I keep collapsed and others which I keep expanded.
This state survives starting and stopping Outlook. If I load another PST file however, all is collapsed.

Is there a setting or tool that expands all folder I want expanded?

[JoeP]

If you close the other PST file, Outlook likely does not keep the folder open/close state. When I open a PST file it is always collapsed. When I open one or more folders in it, Outlook remembers the open/closed folder state as long as I do not close the file.

FWIW, I running Outlook 365 version 2308 build 16731.20170 C2R.

[ErikJan]

Yep, that's what I have too. Problem is that if I temporarily load an additional PST (in my case an 'archive' PST because sometimes I'm searching for an old email), my main PST collapses and if that happens, all folders collapse.
I'm looking for a setting or tool that remembers which folders are always open in my PST and restores that. I guess that can be programmed and I'm hoping that was done before.

[JoeP]

I do not see that. The only PST file I have is the local archive.pst file. It remains expanded when I open another PST file. My main files for mail accounts are all OST files. That may be the difference. With Microsoft, who knows?

[ErikJan]

I do not see that. The only PST file I have is the local archive.pst file. It remains expanded when I open another PST file. My main files for mail accounts are all OST files. That may be the difference. With Microsoft, who knows?

IKf you collapse the top folder and then uncollapse, are the previously open subfolders restored?

[JoeP]

If I collapse any account and re-expand it, all other accounts remain in the state they were before I started. If I have a sub-folder expanded in an account, then collapse the account, and re-expand the account the sub-folder is collapsed not expanded.

[ErikJan]

Interesting. I'm using Outlook for Windows. Latest version Win11 and MS365 (so latest version Outlook).
If you have the same, it must be a setting?

[JoeP]

I have not changed any settings that I can recall regarding the navigation pane. I'm running 64-bit Office. Perhaps you have a wonky addin. Have you tried running in Outlook safe mode - Outlook.exe /safe?

[ErikJan]

No addins (only VBA), no macro's. MSO365/64bit... Weird?

[JoeP]

Yeah, I switched to 64-bit Office some time ago. I never have had many addins, only the ones that come with Office.

64-bit Office is the default for new M365, Office 2019, and Office 2021 installs. If you want to switch between 32-bit & 64-bit (either direction) a complete uninstall and reinstall is required.

[ErikJan]

Why would I want to go back to 32bit? Sorry, don't understand your last comment...

[JoeP]

I missed that you have a 64-bit Office. Sorry. I would not recommend going back.

[ErikJan]

NP... but my problem remains...