I was using Archicad 23, I had removed it from the laptop before. .bak file was giving an error I changed the .bak file extension to .pln file, it gives an error that the plan file cannot be read, what should I do now?
Read this helpful guide prepared by @mtron and edited by @Rubia Torres
.bak? Not .bpn?
Are not .bak files only generated during the save process and removed after? If AC died mid save I would assume that the .bak file would be incomplete and hence most likely unreadable...
I agree with Lingwisyer, a BAK file is not an Archicad Project Backup, you need to look for a file with the same name as your project and having the BPN extension.