warning message

Duplicati -

I’ve noticed for the past couple of weeks that one of the backups configured to use produces this warning message, however, the other folder backing up to doesn’t.

2020-04-21 22:00:21 -04 - [Warning-Duplicati.Library.Backend.Box.BoxBackend-BoxErrorParser]: Failed to parse error from Box

The folder backup that produces this warning message completes and verifies just fine. I’m wondering what might be happening. There is no other message or info in the log that pertains to this.
Thanks for your thoughts!
Dow Hurst

These one-line summaries usually lose the the needed details behind the final result.
Can you try About --> Show log --> Live --> Warning to see if you can get any more?

I tried to run the job and watch the log, but even with Verbose live log turned on, I didn’t see any warnings. I’ll try again later tonight at 10pm when the job normally runs to watch the log.

Intermittent issues can be a pain to catch. If you like, you can set a –log-file. You don’t even need to set –log-file-log-level, because the default level will catch Warnings and anything more severe (e.g. Errors).

I also get these warnings and created a forum entry some time ago with some log information:
Warning Box Backend Error

I created a log capturing Warnings from I get the same error that aschrage does:

2020-05-06 22:00:16 -04 - [Warning-Duplicati.Library.Backend.Box.BoxBackend-BoxErrorParser]: Failed to parse error from Box
Newtonsoft.Json.JsonReaderException: Unexpected character encountered while parsing value: <. Path ‘’, line 0, position 0.
at Newtonsoft.Json.JsonTextReader.ParseValue () [0x002b3] in :0
at Newtonsoft.Json.JsonTextReader.Read () [0x0004c] in :0
at Newtonsoft.Json.JsonReader.ReadAndMoveToContent () [0x00000] in :0
at Newtonsoft.Json.JsonReader.ReadForType (Newtonsoft.Json.Serialization.JsonContract contract, System.Boolean hasConverter) [0x0004a] in :0
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize (Newtonsoft.Json.JsonReader reader, System.Type objectType, System.Boolean checkAdditionalContent) [0x000db] in :0
at Newtonsoft.Json.JsonSerializer.DeserializeInternal (Newtonsoft.Json.JsonReader reader, System.Type objectType) [0x00054] in :0
at Newtonsoft.Json.JsonSerializer.Deserialize (Newtonsoft.Json.JsonReader reader, System.Type objectType) [0x00000] in :0
at Newtonsoft.Json.JsonConvert.DeserializeObject (System.String value, System.Type type, Newtonsoft.Json.JsonSerializerSettings settings) [0x0002d] in :0
at Newtonsoft.Json.JsonConvert.DeserializeObject[T] (System.String value, Newtonsoft.Json.JsonSerializerSettings settings) [0x00000] in :0
at Newtonsoft.Json.JsonConvert.DeserializeObject[T] (System.String value) [0x00000] in :0
at Duplicati.Library.Backend.Box.BoxBackend+BoxHelper.ParseException (System.Exception ex) [0x0007d] in <5e179c0a25f4477cb070f85347eca227>:0

It seems to be benign in that my backups complete, verify, and can recover files if needed. However, these build up over time if not dealt with.

More context might help understand what was going on and whether a retry did what was needed.
Increasing logging level from Warning to Retry should do that. As for the line 0, positon 0, I’ve wondered (along with others) if the network did something odd (like close its connection on you…), however capturing data at that level is technically difficult, especially if the error is very intermittent.

Dropbox: Error reading JObject from JsonReader. Path ”, line 0, position 0 was a case on Dropbox.
If you go for network tracing, note the warning about how you’re capturing unencrypted information.
Encrypted information can be obtained from Wireshark, but would take even more guessing over it.

Easiest and OK result would be to find that whatever upload/download/list/etc. worked OK on retry.

Improved error messages for non-json errors #4195 will possibly help reporting, but it’s not yet in a Beta.

Some servers respond with a text-only (or HTML) output when an error occurs.
In several places, Duplicati expects to read JSON data, and then fails due to the non-JSON text.
In this case, the error message that the server sent is hidden, and only an “invalid json” error message is reported.