In response to your edited message, now that you have the VirtualBox repo in your software sources, VirtualBox will update automatically when you run your update manager. Let's wait and see if it's working though.

Its the same more.. Dont start.

Document is empty.
Location: '/home/linuxmint/.config/VirtualBox/VirtualBox.xml', line 1 (0), column 1.
/home/vbox/vbox-5.2.8/src/VBox/Main/src-server/VirtualBoxImpl.cpp[554] (nsresult VirtualBox::init()).


Fehlercode:
NS_ERROR_FAILURE (0x80004005)
Komponente:
VirtualBoxWrap
Interface:
IVirtualBox {9570b9d5-f1a1-448a-10c5-e12f5285adad}
Callee:
IVirtualBoxClient {d2937a8e-cb8d-4382-90ba-b7da78a74573}

For which of the two VirtualBox launches in my last list of commands does the above error occur (before or after installation of the Extension Pack)?

It dont open. So i dont install this pack. But i have the extension pack install as it was working before when i install it first time. Only after Update it is so. I would like to install wordpress.org the same time. Maybe that is a problem?

Ok. Can you please paste the output from the following command:

linuxmint@linuxmint-ThinkPad-T530 ~ $ ls -la ~/.config/VirtualBox/
insgesamt 324
drwx------ 2 linuxmint linuxmint 4096 Mär 27 16:52 .
drwxr-xr-x 28 linuxmint linuxmint 4096 Mär 25 19:16 ..
-rw------- 1 linuxmint linuxmint 1237 Mär 25 16:51 compreg.dat
-rw------- 1 linuxmint linuxmint 1061 Mär 25 18:46 selectorwindow.log
-rw------- 1 linuxmint linuxmint 990 Mär 25 17:00 selectorwindow.log.1
-rw-rw-r-- 1 linuxmint linuxmint 231881 Feb 27 22:42 vbox-ssl-cacertificate.crt
-rw------- 1 linuxmint linuxmint 1680 Mär 27 16:52 VBoxSVC.log
-rw------- 1 linuxmint linuxmint 1680 Mär 27 16:50 VBoxSVC.log.1
-rw------- 1 linuxmint linuxmint 1680 Mär 25 21:49 VBoxSVC.log.10
-rw------- 1 linuxmint linuxmint 1680 Mär 27 16:24 VBoxSVC.log.2
-rw------- 1 linuxmint linuxmint 1680 Mär 27 13:05 VBoxSVC.log.3
-rw------- 1 linuxmint linuxmint 1680 Mär 26 21:59 VBoxSVC.log.4
-rw------- 1 linuxmint linuxmint 1680 Mär 26 12:53 VBoxSVC.log.5
-rw------- 1 linuxmint linuxmint 1680 Mär 26 12:33 VBoxSVC.log.6
-rw------- 1 linuxmint linuxmint 1680 Mär 26 09:12 VBoxSVC.log.7
-rw------- 1 linuxmint linuxmint 1680 Mär 25 21:50 VBoxSVC.log.8
-rw------- 1 linuxmint linuxmint 1680 Mär 25 21:50 VBoxSVC.log.9
-rw------- 1 linuxmint linuxmint 0 Mär 25 20:53 VirtualBox.xml
-rw------- 1 linuxmint linuxmint 2951 Mär 25 17:00 VirtualBox.xml-prev
-rw------- 1 linuxmint linuxmint 26771 Mär 25 16:51 xpti.dat

The Extension Pack doesn't install into Linux, it installs into VirtualBox, so you need to download the new version and install it every time VirtualBox moves to a different version (or in this case because you uninstalled and re-installed VirtualBox). But please ignore this for the moment while we get VirtualBox working. Also, forget WordPress for the moment.

Right, you will notice that VirtualBox.xml is an empty file (as the error message above stated). I don't know how that has occurred, but let's swap in the backup copy.

The reason for the first copy is to make your own copy of the file independently of VirtualBox's backup process in case that file gets over-written.

Then try launching VirtualBox again.

Ok it is open now. Only 2 from 3 VMs is not accessible

Yes i have install in VB and it works normally before. Its installed more. Must i update this, too?

The 2 VMs written the same error more:
Document is empty.
Location: '/home/linuxmint/VirtualBox VMs/Surfen/Surfen.vbox', line 1 (0), column 1.
/home/vbox/vbox-5.2.8/src/VBox/Main/src-server/MachineImpl.cpp[741] (nsresult Machine::i_registeredInit()).
Fehlercode:
NS_ERROR_FAILURE (0x80004005)
Komponente:
MachineWrap
Interface:
IMachine {85cd948e-a71f-4289-281e-0ca7ad48cd89}

From now on, VirtualBox will update automatically with the rest of your system and software updates. However, each time it does so, you will need to also download the latest Extension Pack and install that into VirtualBox. Then, in each VM, you will need to mount the Extension Pack iso and install it into that operating system (but I assume you know how to do this).

Right, take one of the VMs that isn't working. In what way is it not working and what errors are you getting for it?

Master-Sezer, can you please stop editing your replies and adding further information (often while I am writing my reply). I keep needing to look up at previous posts to see if you have edited them. If you are *adding* information to a post then please put that information in a new post. Many thanks.

Ok, thats great. To install extension pack is easy, or not? Only after install VM when its open i download the right version and install this. Only one time. Or not?

There is written:
Document is empty.
Location: '/home/linuxmint/VirtualBox VMs/Surfen/Surfen.vbox', line 1 (0), column 1.
/home/vbox/vbox-5.2.8/src/VBox/Main/src-server/MachineImpl.cpp[741] (nsresult Machine::i_registeredInit()).
Fehlercode:
NS_ERROR_FAILURE (0x80004005)
Komponente:
MachineWrap
Interface:
IMachine {85cd948e-a71f-4289-281e-0ca7ad48cd89}

Ok, let's go and change that VM's configuration file if we can. First, let's see what is there:

Oh iam really sorry, i dont do this never.

Double-clicking on the extension pack file on the desktop will install it into VirtualBox (I usually close VirtualBox before doing so).

I don't understand your last question - please refer to my previous post where I talk about how and when to install the latest extension pack.