The repair check-witnesses command

Every note the wallet can spend needs a witness: a path proving the note’s commitment is in the chain’s note commitment tree. zallet repair check-witnesses tries to construct one for each note the wallet believes is currently spendable, and reports the block ranges that would have to be rescanned to rebuild the ones it could not.

By default the command only reports. Each range is printed to standard output as start..end, with the end exclusive, and nothing is printed if every note has a witness:

$ zallet repair check-witnesses
2999500..2999750
3000100..3000200

Pass --queue-rescan to queue those ranges to be rescanned the next time the wallet syncs:

$ zallet repair check-witnesses --queue-rescan
2999500..2999750

This is the only way the command modifies the wallet. Rescanning happens on the next zallet start, and only affects how the wallet reads the chain — no funds are at risk either way.

What this command cannot tell you

It examines only notes the wallet holds. A wallet’s note commitment tree can disagree with the chain’s at positions where the wallet has no note of its own, and this command will not notice: it will report that every spendable note has a witness while the wallet is still broken.

So a clean result here is not proof that the wallet’s trees are sound. In particular, if zallet start is exiting with a note commitment tree conflict, this command is unlikely to find anything, and the tool you want is zallet repair truncate-wallet — roll the wallet back to before the conflicting data and let it rescan.