File / program association in Windows 11 (version 26)

[Arcadia]

I have both V25 & V26 installed. For no apparent reason windows (after latest windows update) has suddenly decided that all .pln files are a mystery to it and does not even recognize V26 as a possibility.

I can open files in V26 okay by using the open command in Archicad but I can't double click on the file in explorer to open it (I just get a message that this file does not have any software associated with it). Even old V25 files won't open in V25 if I double click.

Using right click, properties and searching for a program to associate with the .pln doesn't work either. I can see V25 as an option but when I search for and select V26 it just defaults straight back to V25. I had this issue when I had V24 & V25 installed as well and solved it by uninstalling V24. I'm not quite ready to uninstall V25 - is there any other potential fix for this annoying issue?

[Laszlo Nagy]

Robert, also consider that your step will restore file association to Ac26 for the PLN file format only.

You would have to do the same steps for all other Archicad-related file formats you want to be opened with AC26.

[Robert Horvath]

Lászó,
I think you only need to register 2-3 extensions at most. It is also a consideration that installation requires administrator rights.
In many places it is difficult and expensive to hire a system administrator to do this task which can be done independently and quickly.

[Laszlo Nagy]

That is a valid point.