[SOLVED] Discover - Unable to load applications

[royleith]

This bug has been coming up regularly over the releases, but it has not been a problem for me - until now with 21.10.

When I run plasma discover, it says:

Unable to load applications
Please verify Internet Connectivity

Cannot refresh cache whilst offline

I checked another machine which had no such problem.

I tried a 'Live DVD' image (the one I used on a USB drive to install it) and that was fine.

I went for the nuclear option and reinstalled Kubuntu.

The problem remains.

The problem is caused by something in my /home/ directory. I ran the program from the terminal and got:

** (process:41401): CRITICAL **: 15:37:48.359: Unable to open temporary cache: Unable to open temporary cache file: Permission denied


** (process:42106): WARNING **: 15:43:49.005: Unable to retrieve all components from session cache: Can not perform this action on an unopened cache.

It appears that it is nothing to do with the Internet connection (which is fine and which Discover, dutifully, reports and installs updates). I have Googled for the location of the cache without success. I suspect there is an old version in place with inappropriate permissions. I have searched the home folder for plasma, discover and cache without finding such a file. Does anyone know where Discover tries to set up its temporary cache?

[Snowhog]

Check that NOTHING in your /home/username is owned by root.

[royleith]

Check that NOTHING in your /home/username is owned by root.

I was terrified that some of my complex wine stuff might die, but I used krusader to nuke the whole folder.

It did not resolve Discover. However the wine stuff had died! I had not completed the Kubuntu reinstall and once the wineHQ release was in place, all was well.

It must be a duff script file in the /home/ directory. I will try to set up a new user and see if that works.

[royleith]

I created a new user and Discover works perfectly for that user. It is still failing in my main account. I shall do a manual comparison of the two /home/ folders to see if anything crops up.

[royleith]

I found some added folders in .cache:

/home/<ID>/.cache/discover/odrs

/home/<ID>/.cache/discover/images

Deleting them had no effect.

I found that the files for 'Recommended' apps are fully populated, but the apps do not appear when Discover starts.

I also found new items added to /.cache/discover so that is not where the 'temporary' cache is created - unless it is the creation process, itself which is not working. So, why would it work for another user?

[oshunluvr]

Check that NOTHING in your /home/username is owned by root.

Seems you haven't done the above yet.

Try this in konsole:

ll -R ~ |grep root

[royleith]

Seems you haven't done the above yet.

Try this in konsole:

ll -R ~ |grep root

I used Krusader in root mode to change the ownership and permissions for everything in my /home/ folder. I'm a gui person.

I tried your command line check, but I get

ll: command not found

After some googling I found my distro did not implement the shortcut. I tried;

ls -al -R ~ |grep root

I had to unmount a couple of large drives to refine the results, but found a folder:

~/.cache/appstream

owned by root and dated February this year. which was when I upgraded to the 21.10 release. I don't know why krusader did not change the ownership and permissions of this folder as all the other files and folders that I checked had their ownership and permissions changed.

Whatever, the folder was empty and, after changing the ownership, Discover is now working. Thanks for the command line tip. Strangely, no files are added to the folder whether the discover app is running or after closure.

Any advice on how to add [SOLVED] to the title?

[arsivci]

A useful trick when I reinstall without formatting my home partition is to create a new user. Say your current user name is OLD. Reinstall and create a user NEW. All files belonging to old user will be in directory /home/OLD. Move your documents, videos etc from OLD to NEW; it is just a few extra clicks. All old DOT files will remain in /home/OLD. If you specifically want one, like Firefox, copy it to NEW. When finished, remove the OLD directory. There will be no artifacts and you will have a clean system.

*** This requires that you have a separate /home partition.