After a SketchUp desktop crash, check the Welcome window for a recovered model. For an earlier saved revision on Windows, inspect the matching SKB backup. If a saved SKP was deleted, use existing copies or storage recovery. Autosave and backup files serve different purposes and depend on what existed before the loss.

Check the recovered model after a crash
Open SketchUp desktop and inspect Recovered entries in its Welcome window. If the window is hidden, current documentation provides Help > Welcome to SketchUp. Open the candidate, inspect its content and use Save As to preserve it under a new name.
SketchUp’s current General preferences documentation explains that autosave writes temporary data, separate from the opened model. That data can survive a crash but is removed on normal exit. Do not close or reset a useful recovery session before saving its model. This desktop route should not be assumed to describe SketchUp for Web or every older desktop version.
Recover an earlier saved backup
On Windows, a matching .skb normally sits beside the .skp when Create backup was enabled. Backups represent the previous saved model and are not created until the model has been saved again after its initial save. Inspect Window > Preferences > General for the setting in the documented Windows interface.
Preserve both files. Make a working copy of the SKB, give the copy a distinct name with .skp, and open it in SketchUp. Ensure Windows displays extensions so the new file is not accidentally named .skp.skb. SketchUp describes its backup convention in Troubleshooting a corrupted file.
Check actual cloud or disk copies
If the model was saved to Trimble Connect, inspect the project’s available version facilities under the correct account before replacing a local copy. Do not assume another synchronization service retained an older version, or that a local autosave was uploaded.
For a deleted local SKP with no usable backup, check Recycle Bin and the original folder’s backup. XRecovery can search remaining files on readable media and save candidates to another physical device. Open a recovered SKP copy in a compatible SketchUp version and inspect the model. If it needs structural repair, follow the application’s own repair or backup route.
Verify a model, not just its thumbnail
Open the selected candidate in a compatible SketchUp desktop version. Inspect known geometry and dimensions, groups, components, tags and scenes. Check materials/textures and any linked resources required for the job. A model can open yet contain the wrong revision or missing texture assets.
Compare a key view or exported drawing against a trusted reference. Save a separate working SKP, close and reopen it, and inspect representative scenes again. If a backup lacks the final edits, record its cutoff before rebuilding them. Keep the old SKP, SKB and recovered candidates until the chosen model is verified and preserved.
For the next step, see Document Recovery: Deleted, Unsaved, Overwritten or Damaged?.