So after talking to Backblaze, they said there is no way to move data inside the same bucket. So this explains why nothing works, or only sort of works.

I guess I spoke too soon. It can move files under 200M but trying to move files that are 3.8G, it times out.

The solution is to use the S3 Compatible API and not the Backblaze B2 API.

I can't open a support case because I'm using the freeware version of Explorer.

If you try to open a support case it says to get support from the forum.

It's a small amount of large files, and it's using the legacy format (I think we determined that earlier.) The files are anywhere from 40M to 1.5G.

4 threads. It's the purchased version. The ISP upload speed on the site isn't the best but S3 was noticeably faster.

The chunk size was the issue. The backup works without stopping now.

Also Backblaze is awfully slow. Uploads seem capped at about 20mbit.

Well before I even finished the above post, I got a response from support. They said the chunk size was too high; it's set to 1GB. They recommend setting it back to the default of 10MB. I'll see if that's the issue!

Well it keeps happening. I submitted a support request. I also figured out how to get the logs and see a lot of:
2021-09-09 10:32:48,330 [CL] [10] WARN - Generating chunks is idle for 675 minutes. Next chunk: 3. Object: xxxx
and
2021-09-09 10:33:18,036 [CL] [36] ERROR - On chunk finish. Cnunk info: Status:Cancelled Number:2 Length:1048576000 IsLast:False Offset:1048576000, Exception: CloudBerryLab.Client.Chunks.NotAllChunksUploadedException: Not all chunks were uploaded. False
and
Unable to write data to the transport connection: An established connection was aborted by the software in your host machine.

No disk errors in the Windows event log.

The other log for the S3 plan, goes back to 2018 and I don't see anything like the above.

What sort of erks me is the program doesn't stop with some message that there's a problem. It just.. stops and sits there like it's still doing the backup. This is all just to test Blackblaze and so far it's not looking good.

Thank you David and sorry for any confusion. The version is 7.1.3.28 . It's doing a file backup. The backup format is legacy, I believe. Which is interesting; I cloned the S3 plan to make the BackBlaze plan, and I guess it carried over the legacy format because it doesn't have the same options for retention as when I use the wizard from scratch. So, since it's barely backed up much of the 360G it has queued, I may stop it and start over creating a new plan from scratch.

The S3 backup has been running for a few years without an issue, so I was surprised to find it stalled on the Backblaze backup. Hopefully it was just a fluke.

Whoops, it's stand-alone.

I don't have support on that license so I didn't think they'd respond. After reading other posts I thought my only option was the forum.