V7 file structure: broken and scrambled

I jumped directly from v5 to v7 and probably “missed” some important changes that occurred along the way. In particular the v7 “Project” structure appear to be not at all like the ones of v5
A complication is that I converted an Altium project (not built by myself) to KiCad v7 and I have no idea of how that has complicated things re: the file structure.
I am also confused about how the operations “save as” and “save a copy” differ.
Net result:
As a result of trying to streamline my file & folder structure surrounding this converted Altium project, I have created a perfect storm. From the scrambled mess, I have managed to salvage the latest working PCB and the latest working Sch, and have put them in the same folder with the same names (different extensions, obviously), but the KiCad.pro does not recognize them…
—> Is there any way to fix this, so that I can continue with a single project without having to resort to re-doing all my previous work (converting from Altium, and then spending 30+ hours working on the PCB and schematic and symbols and footprints)?

The root schematic sheet has to have same name as the project file, same with the pcb file.

What do you mean by

If your project file is KiCad.pro then your root schematic sheet must be KiCad.kicad_sch otherwise it will not be considered as main schematic file. And your pcb must be KiCad.kicad_pcb, otherwise it will not be considered that project’s pcb file. Keep in mind also that in kicad one project = 1 pcb so if you have multiple pcbs then you either have to make a combined panel pcb out of them or create separate project for each.

Ah. Thanks for that…seems obvious now, but I had not changed the pcb & sch file names to be precisely the same as the [xxxxx].pro name.

Oddly now, the individual sheet names are NOT displayed in the directory tree for the project, even though they exist inside the project’s Folder; the schematic recognizes them

Yes, somewhat counterintuitively, kicad file tree in the project manager only shows stuff that it considers NOT part of the project. Presumably so that you can open them in external tools directly from the tree.

Well, yes, that IS counterintuitive! I was totally unaware of that fact. So the tree shows only the items created within the Project (sch, pcb…? Gerbers files ?), and all the supporting documents you might choose to stuff in there (datasheet pdfs, for example). Any idea of why the footprint / symbol cache for the project is not displayed?

Fp/symbol cache are inside the pcb/schematic, they are not separate files like they used to be in previous versions.

Edit: to clarify, fp cache became part of pcb in v4, symbol cache in v6. fp-info-cache file is not part of the project, it’s just there to speed up loading the fp libraries.

Ahhhhhhhhhh.
Thanks.
Are you using v8 yet? Are there more changes in file / project handling there?
I noticed that the conversion from Altium file seems to have resulted in some peculiar behavior. I cannot pin that down precisely, to relate that to you, but some things are as you say 'counterintuitive". Any idea of whether and how I should re-name the converted Altium layers (many are still appearing as M#)

There are no file structure changes in v7-v8 to my knowledge but I haven’t designed anything in v8 yet.

If you have specific issues related to altium conversion it’s better to open a new topic for those, I never used that importer.