I can confirm this behavior: when starting konqueror, it show to me "Die Aktion lässt sich nicht ausführen" , "Ungültiges Adressformat (URL)".  
However I have configured Konqueror to start with an empty page.
When entering an file URL, e.g. "/tmp", the tree is displayed but clicking on an item does not start an action (e.g. open the folder).

With this error, Konqueror is currently completely unusable for me.
This is a mess because Konquerer provides some productive, unique features (e.g. tabbed mode, HTML browsing + file management) which I really use for my daily work in the office and I am currently delaying updates to other computers to prevent this error.


SOFTWARE/OS VERSIONS
Linux: Debian 12 (bookworm, Testing)
KDE Plasma Version: 5.26.90
KDE Frameworks Version: 5.102.0
Qt Version: 5.15.8
Kernel-Version: 6.1.0-3-amd64

(In reply to Reiner Nix from comment #1)
> I can confirm this behavior: when starting konqueror, it show to me "Die
> Aktion lässt sich nicht ausführen" , "Ungültiges Adressformat (URL)".  
> However I have configured Konqueror to start with an empty page.
> When entering an file URL, e.g. "/tmp", the tree is displayed but clicking
> on an item does not start an action (e.g. open the folder).
> 
> With this error, Konqueror is currently completely unusable for me.
> This is a mess because Konquerer provides some productive, unique features
> (e.g. tabbed mode, HTML browsing + file management) which I really use for
> my daily work in the office and I am currently delaying updates to other
> computers to prevent this error.
> 
> 
> SOFTWARE/OS VERSIONS
> Linux: Debian 12 (bookworm, Testing)
> KDE Plasma Version: 5.26.90
> KDE Frameworks Version: 5.102.0
> Qt Version: 5.15.8
> Kernel-Version: 6.1.0-3-amd64

Which version of Konqueror are you using? The original report is about an old version, but since you mention Frameworks I guess it's more recent than that. Also, do you start Konqueror by clicking on the quick-launch icon in the Plasma panel? If so, have you tried running Konqueror directly from the application launcher or from KRunner (Alt+F2)? Do you get the same results? There's a bug with the quick launch icon which causes it to run the wrong component of Konqueror, but it should only affect  the start page. Entering any other URL in the location bar should work correctly.

Hi Stefano,

Sorry for the late answer, I was a bit ill.

> Which version of Konqueror are you using? The original report is about an old version, but since you mention Frameworks I guess it's more recent than that. 

The problem is found using 
- konqueror:  22.12.2
- KDE frameworks 5.102.0
- QT: 5.15.8


I have another host also running with Debian Testing but without some of the latest updates,
*were the problem is stil not present*, with following versions:
- konqueror:  21.12.3
- KDE frameworks 5.100.0
- QT: 5.15.6


> Also, do you start Konqueror by clicking on the quick-launch icon in the Plasma panel? 
Yes, I have started Konqueror with a single click on the icon in the Plasma control panel and it shows "Die Aktion lässt sich nicht ausführen".

When trying to start Konqueror by clicking on the icon on the Desktop, it opens a tree view with the location set as document path. But this is broken. When selecting an entry, the address line gets updated but the tree view does not change. Opening an entry with click is not possible.

> If so, have you tried running Konqueror directly from the application launcher or from KRunner (Alt+F2)? 
> Do you get the same results? There's a bug with the quick launch icon which causes it to run the wrong component of Konqueror, 
> but it should only affect  the start page. 
> Entering any other URL in the location bar should work correctly.
Yes, opening is possible. The result shows only the broken tree view.

And starting konqueror from konsole ("konqueror /home") shows again the broken tree view.
But then following messages are displayed:

reiner@titus:~$ konqueror /home
(directly after entering the command)
Hspell: can't open /usr/share/hspell/hebrew.wgz.sizes.
kf.sonnet.clients.hspell: HSpellDict::HSpellDict: Init failed
QDBusConnection: error: could not send signal to service "" path "//tmp/closeditems/_1.270" interface "org.kde.kconfig.notify" member "ConfigChanged": Invalid object path: //tmp/closeditems/_1.270
(after stoping konquerer with the close-button)
QDBusConnection: error: could not send signal to service "" path "//home/reiner/.local/share/konqueror/closeditems_saved" interface "org.kde.kconfig.notify" member "ConfigChanged": Invalid object path: //home/reiner/.local/share/konqueror/closeditems_saved
QDBusConnection: error: could not send signal to service "" path "//home/reiner/.local/share/konqueror/closeditems_saved" interface "org.kde.kconfig.notify" member "ConfigChanged": Invalid object path: //home/reiner/.local/share/konqueror/closeditems_saved
QDBusConnection: error: could not send signal to service "" path "//tmp/closeditems/_1.270" interface "org.kde.kconfig.notify" member "ConfigChanged": Invalid object path: //tmp/closeditems/_1.270


P.S. I have found another recent similar problem report in the web, 
see https://forums.opensuse.org/t/konqueror-is-going-krazy/153955

Cheers,
Reiner

(In reply to Reiner Nix from comment #3)
> Hi Stefano,
> 
> Sorry for the late answer, I was a bit ill.
> 
> > Which version of Konqueror are you using? The original report is about an old version, but since you mention Frameworks I guess it's more recent than that. 
> 
> The problem is found using 
> - konqueror:  22.12.2
> - KDE frameworks 5.102.0
> - QT: 5.15.8
> 
> 
> I have another host also running with Debian Testing but without some of the
> latest updates,
> *were the problem is stil not present*, with following versions:
> - konqueror:  21.12.3
> - KDE frameworks 5.100.0
> - QT: 5.15.6
> 
> 
> > Also, do you start Konqueror by clicking on the quick-launch icon in the Plasma panel? 
> Yes, I have started Konqueror with a single click on the icon in the Plasma
> control panel and it shows "Die Aktion lässt sich nicht ausführen".
> 
> When trying to start Konqueror by clicking on the icon on the Desktop, it
> opens a tree view with the location set as document path. But this is
> broken. When selecting an entry, the address line gets updated but the tree
> view does not change. Opening an entry with click is not possible.
> 
> > If so, have you tried running Konqueror directly from the application launcher or from KRunner (Alt+F2)? 
> > Do you get the same results? There's a bug with the quick launch icon which causes it to run the wrong component of Konqueror, 
> > but it should only affect  the start page. 
> > Entering any other URL in the location bar should work correctly.
> Yes, opening is possible. The result shows only the broken tree view.
> 
> And starting konqueror from konsole ("konqueror /home") shows again the
> broken tree view.
> But then following messages are displayed:
> 
> reiner@titus:~$ konqueror /home
> (directly after entering the command)
> Hspell: can't open /usr/share/hspell/hebrew.wgz.sizes.
> kf.sonnet.clients.hspell: HSpellDict::HSpellDict: Init failed
> QDBusConnection: error: could not send signal to service "" path
> "//tmp/closeditems/_1.270" interface "org.kde.kconfig.notify" member
> "ConfigChanged": Invalid object path: //tmp/closeditems/_1.270
> (after stoping konquerer with the close-button)
> QDBusConnection: error: could not send signal to service "" path
> "//home/reiner/.local/share/konqueror/closeditems_saved" interface
> "org.kde.kconfig.notify" member "ConfigChanged": Invalid object path:
> //home/reiner/.local/share/konqueror/closeditems_saved
> QDBusConnection: error: could not send signal to service "" path
> "//home/reiner/.local/share/konqueror/closeditems_saved" interface
> "org.kde.kconfig.notify" member "ConfigChanged": Invalid object path:
> //home/reiner/.local/share/konqueror/closeditems_saved
> QDBusConnection: error: could not send signal to service "" path
> "//tmp/closeditems/_1.270" interface "org.kde.kconfig.notify" member
> "ConfigChanged": Invalid object path: //tmp/closeditems/_1.270
> 
> 
> P.S. I have found another recent similar problem report in the web, 
> see https://forums.opensuse.org/t/konqueror-is-going-krazy/153955
> 
> Cheers,
> Reiner

I just realized the error you're getting is different from that in the original report (I don't speak German, so I had to use Google Translate, but I only did so for the message in the original report and automatically assumed that yours was the same), so most of the information I asked you were irrelevant to your situation. Sorry for wasting your time. Now, some more useful questions:
- does this happen only for directories or also for other kinds of URLs? For example, does running "konqueror /path/to/pdf_file.pdf" work? And what about "konqueror https://www.google.com"?
- if it only happens for directories, it means that there's something not working between Konqueror and the Dolphin part. Just to be sure, could you please check that Dolphin itself is installed and that it works?
- could you try creating a new user and check whether it has the same problems? This way we can rule out a configuration issue.

As soon as I have time (unfortunately, that could mean next Sunday), I'll try setting up a Debian virtual machine so that I can have a look at what happens on a new system.

>I just realized the error you're getting is different from that in the original
>report (I don't speak German, so I had to use Google Translate, but I only did
>so for the message in the original report and automatically assumed that yours
>was the same), so most of the information I asked you were irrelevant to your
>situation.

Hm, maybe its another error with similar result.
However the observed message is the same and then I found some more problematic aspects.
>>When starting Konqueror, the following error message is shown:
>>
>> Die Aktion lässt sich nicht ausführen
>> Nicht dokumentierter Fehler
This could be translated as "The action cannot be executed. Undocumented error"


> does this happen only for directories or also for other kinds of URLs? For
> example, does running "konqueror /path/to/pdf_file.pdf
In this case Konqueror starts and shows address "konq:blank" (I have configured to start with an empty page)
and additionally Okular ist started and opens the specified pdf file.
So this seems to be ok.


> And what about "konqueror https://www.google.com"?
This also works fine: konqueror starts and opens the google search page. 
It is possible to enter a search term.
The usual search completion is working and a result is shown.


> if it only happens for directories, it means that there's something not
> working between Konqueror and the Dolphin part. Just to be sure, could you
> please check that Dolphin itself is installed and that it works?
Yes, Dolphin is installed and is working without any obvious problem.
Although I prefer to use Konqueror because it is a bit more suitable for some features,
Dolphin is working as expected.


> could you try creating a new user and check whether it has the same problems?
> This way we can rule out a configuration issue.

After creating a new user and starting Konqueror it is working fine.
Here it is.  Thus it's a configuration issue, 
I guess introduced during migration to a new version?

I have deleted $HOME/.config/konquerorrc and restarted Konqueror,
but unfortunately this does not help.

Please could you give an advice which configuration files may cause the problem?

> After creating a new user and starting Konqueror it is working fine.
> Here it is.  Thus it's a configuration issue, 
> I guess introduced during migration to a new version?
> 
> I have deleted $HOME/.config/konquerorrc and restarted Konqueror,
> but unfortunately this does not help.
> 
> Please could you give an advice which configuration files may cause the
> problem?

There's also a konqueror directory in ~/.local/share which contains some Konqueror settings, but I don't think it contains anything related to your problem. You can try renaming it and check whether something changes, however. Take care because bookmarks are also stored in this directory (in .local/share/konqueror/bookmarks.xml). Another file you could try is .config/mimeapps.list, which contains settings about the applications used to open different kind of files. Aside from this, unfortunately I don't have any other suggestions.

By the way, could you please post a screenshot Konqueror when you launch it with a directory as argument? I'm not completely sure I understood what you're seeing.

Thanks