Restoring Lost Properties After Replacing Old Classifications in Archicad 26

ananas — Mon, 13 Oct 2025 10:21:58 GMT

Hi guys, maybe someone here can help me!

I replaced all the old classifications from Archicad 23, 24, and 25 with my current Archicad 26 ones.

I also deleted the old properties (Eigenschaften), and now I’ve lost some of them.

Does anyone know if it’s possible to relink the properties from an old file to my current one while keeping the Archicad 26 classifications?

Thanks in advance for any help!

Re: Restoring Lost Properties After Replacing Old Classifications in Archicad 26

Benedek Gaszpor — Mon, 13 Oct 2025 10:22:56 GMT

Hi @ananas,

If I understand your issue correctly:

You have your own amazing properties that are Expressions and some of them are referring to other properties from your property list.

Then:

You have a project with a "Classification_24" system and the placed elements are classified by this system; Let's say Classification_24/Wall.
You have created a new "Classification_26" system and set the placed elements' classification by this system as well; Let's say Classification_26/Wall.

Now you deleted the Classification_24 system and all the linked properties with it.

Thus all the placed labels that are pointing to a property from the Classification_24 system resulting in an error.

You can export a classification system (with the connected properties) from a project file and then import it into another project file.

Since this is and XML export, and Archicad hasn't been all that overhauled regarding the property manager between AC24-AC26, you can read your AC24 classification XML into your AC26 project.

After this, you still have to manually relink all the properties in your relations.

As you see in the attached picture, the wall here now knows again (, after manually setting it back up again,) that it is classified by the "AC24 Test Classification" system, and in the AC24 Test Property it even has data (although it will go to the default value...)

But the placed label gives back the #... For from the label's perspective the stuff it was referring to is missing.

Even though for us, mere flesh and bone mortals, the data seems the same since they have the same name, for the machine they are new records...

Now you might be able to tweak the XML in a text editor, so the brought in <Key> values match, but I have never played with that before in this regard...

Your best bet, if you have a manageable number of properties to fix, is to go through them manually, or if you haven't gone too far into the project just to revert back to an earlier version.. if possible... and fix your issue there or just live with the old classification system.

Hope it helped in some way.

Or that some other gurus can give you some more useful answer.

Cheers,

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Restoring Lost Properties After Replacing Old Classifications in Archicad 26

Re: Restoring Lost Properties After Replacing Old Classifications in Archicad 26