Warning message - Expected there to be a temporary fileset for synthetic filelist (...), but none was found?

[ts678]

@henryg

Only since updating to 2.0.4.15_canary_2019-02-06, but that could be coincidental.

I suspect coincidental. There are many of these in the forum. Here’s an early one, with an explanation:

@kenkendk

A synthetic filelist is a list of files that Duplicati creates after it has been interrupted, in an attempt to give access to as much as possible. The synthetic filelist is used by taking the previous file list, and adding/updating new files where data was successfully uploaded. It does not remove files, and it is not a real disk-snapshot, hence the name “synthetic”.

The warning is that Duplicati expected the code to generate a synthetic filelist and mark it temporary (i.e. in-progress), but no temporary filelist was found (either it was removed, or it was not temporary, meaning it was uploaded).

Why it happens is a bit harder to figure out. It is a warning because it is unexpected, but most likely does not do any harm.

I think I found the bug’s source. See Expected there to be a temporary fileset for synthetic filelist #2506. Feel free to post your messages to see if you got odd names of dblock, dindex, or too-old dlist files too.

Does the idea that you had some interrupted backups appear to match your logs or your recollections?

The warning says you didn’t get the bonus visible-for-restore version based on work before interruption. Possibly you weren’t even expecting one though. Any issues arising would be from interruption, not this.

Duplicati by default verifies a sample of destination files. You can raise –backup-test-samples if you like. You can even run the test command in a job’s Commandline for all samples if you have time/bandwidth.