The app fails at the align step right away

Usually a GPU driver issue. The app ships with a recent CUDA runtime that needs a current NVIDIA driver. Update to the latest driver and try again.

Interior scan won't align all the rooms

Multi-room interiors are the hardest case for alignment: each room has its own lighting, doorways give the matcher very little overlap to work with, and repeating layouts or décor can fold two rooms into one.

Try these in order:

Turn off the Global mapper (GLOMAP). On the Alignment tab, switch GLOMAP off so the app falls back to the incremental mapper. It registers rooms one frame at a time instead of solving everything at once, which is much more robust across doorways — slower, but it usually picks up the rooms GLOMAP drops. See Global mapper.
Shoot the doorways. Rooms only link where the footage overlaps. Walk slowly through each doorway and pause so consecutive rooms share plenty of frames — a quick step through a door rarely gives the matcher enough to connect on.

Still stuck? Note which step failed and what the log said — that's the fastest way to a diagnosis. Then ask on our Discord and we'll help you figure it out.