Why SketchUp says the file is not a SketchUp model
SketchUp shows "This does not appear to be a SketchUp model" (or "File not found or invalid")
when the file doesn't look the way it expects from the first bytes to the last. Since SketchUp
2021 a .skp file is a short header followed by a packed archive: pictures, materials, styles,
and, written last, the geometry itself, with a table of contents at the very end. If the save
stops before that end (the computer crashed, the disk filled up, the laptop slept, OneDrive or
Google Drive synced a half-written file), the table of contents is missing and SketchUp refuses
the whole file, even though most of the model may still be in it.
Another common pattern: the file has the right size but is zeros from some point on, or from start to finish. The sync service or the disk reserved the space and the contents never arrived.
What this page does with such a file
Upload the .skp above. The file is read part by part, without needing the table of contents:
- the result page says which SketchUp version made it, and exactly where the damage starts ("from byte 11,534,336 on, 90% of the file, only zeros", for example);
- every component and group that was written completely is recovered, with its faces, materials, textures and tags, and the one that was being written when the save stopped is recovered as far as it got;
- the model is written again as a SketchUp 2017 file that every SketchUp from 2017 on opens, and as STL, OBJ and GLB;
- when the geometry part survived whole and only the end of the file was lost, you also get the file repaired in its own version, scenes and styles included.
If the list of what is placed where was in the lost part, the recovered components are lined up along the red axis for you to move back into place. The thumbnail stored in the file shows how the model looked at its last good save.
When nothing is left
A file that is zeros from start to finish holds nothing of the model, and the page tells you so
plainly instead of producing an empty file. It also lists where SketchUp and your cloud service
keep older copies: the .skb (Windows) or .skp~ (Mac) backup next to the file, SketchUp's
RecoveredFiles and Autosave folders, OneDrive, Google Drive and Dropbox version history,
Trimble Connect, and Windows Previous Versions or Time Machine. Upload any copy you find here:
damaged copies are read the same way, and with several files the most complete one is used.
More about what this tool reads and writes: SketchUp File Repair and Converter (SKP to 2017, STL, OBJ).