One of the ways I mitigate the performance and management issues with folders in the Portal directory is to replace key folders with folder providers (e.g., Amazon). This has greatly improved performance and decreased management times with each of the websites I've done this with. You can even do this with existing folders.

Regarding the management aspect... Backups and restores especially are far less time-consuming and much more manageable in all aspects. It also helps with more enterprise situations when key/strategic files/folders are on an external API-based system like Amazon.

We have seen the same on several installations.
Stefan posted a similar question in the DNNConnect FB group (march 13) related to CKEditor file browser and our conclusion is that is it's a core issue.

Here's the post Timo was mentioning: https://m.facebook.com/groups/756753714471271?view=permalink&id=1624906114322689

I remember reading your FB post. AFAICR, Sebastian did not respond?

Time to dig some further in the routines that handles permissions & folders.

Ernst Peter,

This is something that has plagued the installation for quite a while, there are a few things that can impact the overall performance

* Number of Folders
* Number of Permissions Applied to Folder
* Number of User folders with no content
* Server Size
* Lack of DB Management
* Use of Auto-Sync File System can exaggerate errors.

Often times I find that rebuilding the indexes on the tables related to the files, folders, permissions can help improve performance, as most often times individuals do not do any regular index management. However, long-term this is something that needs to be addressed.

Mitch, Thank you for your feedback. All the things you mention are already taken care of. Decent database maintenance, mega sized server, well defined DNN scheduled tasks, cleanup routines, no auto-sync, etc.

One thing different from normal is that all files are stored as “secure” files (.resources).

We have removed a lot of files and folders that the client will need no earlier than the end of this year, performance is now back to normal.

We will try to recreate the problem locally in a dev environment and do some debugging

AFAIK, Ingo improved performance of browsing images in latest version of his original CK editor provider.
In general, the files and folder management has performance issues, caused by suboprimal indexes and many database calls.
On sites with many registered users, a major performance decrease is caused by nested user folders (and folder permissions) created for every user upon login, even if he never uploads a single file. IMO this could be fixed by creating user folder only when needed and "fake" permissions in the API (I never saw permissions for user folders been modified by an admin).