Problem subscribing folders

[LeoGraper]

Hello there fellow fora users, let me start with telling who I am (didn't see a specific portion to do that).
My name is Leo Graper and I work at the Resistance Museum in Gouda (Netherlands).

Scenario;
We used to use a Webmail app of our provider SoHosted in the Netherlands.
As it has its ups-and-downs we wanted to use Outlook 2010 with IMAP access.
This works, but the folders underneath the Inbox weren't visible.
I found out via our alternative mail being RoundCube the subscriptions weren't set on all subfolders.
So I went to the Map settings and tried to turn them ON.
This worked, RoundCube saw a lot more and also O2K10.
When we went back to the subscription part we saw that the subscriptions were turned off again!
Strange, so we started with one folder and subfolders, and went to the email, all was there, we did this for say 10 folders, and all of a sudden they were turned off again.
It's driving us crazy and mad!
So, is there something wrong in RoundCube, are the maximum values I don't know about?
I'm not sure how many folders there are, my best guess is about 40 folders and within these it depends, but at least more than 200 grand total.

[LeoGraper]

Really? Nobody?

[rm13]

What version of Roundcube are you using?

It sounds like Outlook and Roundcube are both fighting over the subscriptions.

I'm only familiar with Dovecot using Maildir as an IMAP server, it has one subscriptions file of the folders that are subscribed. Roundcube updates this file according to the Settings: Folders tab. Not sure how Outlook would handle another client changing those subscriptions.