"No transaction is active on this connection"

I get this error:

2019-08-26 21:29:11 -05 - [Error-Duplicati.Library.Main.Operation.BackupHandler-FatalError]: Fatal error
System.Data.SQLite.SQLiteException (0x80004005): unknown error
No transaction is active on this connection
   en System.Data.SQLite.SQLiteTransactionBase.IsValid(Boolean throwError)
   en System.Data.SQLite.SQLiteTransaction.Commit()
   en Duplicati.Library.Main.Operation.Common.DatabaseCommon.Dispose(Boolean isDisposing)
   en Duplicati.Library.Main.Operation.Common.SingleRunner.Dispose()
   en Duplicati.Library.Main.Operation.BackupHandler.<RunAsync>d__19.MoveNext()

It is persistent after database recreate (delete and rebuild); actually after recreating the database, the first backup completes without problems, but the second one gives this error again.

This error is different from what others report: there is no rollback here, there is no “Unexpected number of remote volumes detected: 0!”, there is no “cannot commit - no transaction is active”, no other error message before this one.

The backup is to a local disk, which has 0.5 TB free (the source disk has 100 GB, with a handful of tiny files to be updated from the previous backup – several MBs or less). The TEMP disk has 2 GB free.

I have several backup sets, but only one has this problem. They all have the same configuration (backup to the same local disk and with the same TEMP disk), differing only in the source directories.

How can I solve the problem, other than discarding the existing backup?

(BTW, any way to have more descriptive error messages, such as the values of the arguments of the function calls in the trace?)

Probably impossible to say for seemingly never-before-seen error with a completely generic stack trace, which seemingly is just saying that Duplicati somehow thought it was in a transaction when it was not…

What have you tried? Restarts, reboots, Repair after seemingly successful Recreate, –list-broken-files?

Stack trace is up to .NET Framework, but a web search shows people asking about that but not getting it. There’s also some concern about be-careful-what-you-wish-for, as this is a great way to reveal too much information that should be confidential, e.g. personal information, passwords, etc. A debugger could help, however nobody else can debug unless you can find reproducible steps that somebody else can look into.

Can you add –log-file option at a modest –log-file-log-level=Information, to get an idea of error sequence?