Backing up from iCloud Photos
Jan 13, 2021
I'm having some issues with backing up my photos from iCloud Photos.
I have the iCloud app for Windows 10 installed and have my photos and videos in iCloud Photos syncing to my PC. I have not changed any of the "Always keep on this device" or "Free up space" settings in this folder.
When backing up this iCloud Photos directory using Bvckup 2, I have encountered many errors. The error is: This file is stored online and there's no local copy. ReadFileAsync() failed with 426. Context: 0 65536.
I had hoped that Bvckup 2 would be able to download these files on demand when trying to access them, transfer them to the backup drive and they would be removed from the local disk in due course. It does seem to be able to do this, but only with some files as the error has occured with 7722 files out of the total 9094.
Is there any way to remedy this? I'd rather not have to have the files always kept on my system disk as the total size is around 100GB and I think, with ongoing backups, future files would encounter the error unless the "Always keep on this device" property was applied to them.
Thanks in advance!
Alex Pankratov :
Jan 14, 2021
Bvckup2 works at a file system level. It is entirely oblivious to the exact nature of a storage facility that it's being asked to backup from or to. It can be a local drive, a remote share or, as in your case, an emulated virtual device fronting a cloud storage.
As such, the only way the program can signal to a cloud storage client - iCloud, OneDrive, Dropbox, etc. - that it needs a local copy of a file is to open that file for reading.
This would normally trigger the download and the file open request would not complete until the download starts. Reading from the file should follow a similar pattern - if a requested file part is not present locally, the request will pend until this part is downloaded.
Error 426 stands for ERROR_CLOUD_FILE_REQUEST_TIMEOUT, meaning - and I am guessing - that iCloud client is having trouble talking to iCloud. Regardless of the cause, it's an issue with the iCloud software.
You can try and reduce the IO load on the iCloud client by switching Backup Settings > Processing to "One step at a time".
In theory, you can also add 426 to a list of retryable errors, so that Bvckup2 would repeat the same backup step X times if it runs into this error. See  for details.
Finally, once you have the initial backup done, the backup job can be set to skip over offline files on subsequent runs. See  and  for details.
All in all though, the root cause lies with the iCloud software and that what needs tuning.
Jan 14, 2021
Thanks for the information! I'm trying using the "Execute one step at a time" option and will report back as to how it goes.
Jan 20, 2021
I am still facing the same issues. Enabling the "Execute one step at a time" option seemed to help a little but not a lot. I also tried to apply the "Always keep on this device" option for all of the photos and videos in the folder but about half of them were stuck on "Sync pending" status.
I recognise this is an issue with iCloud for Windows 10 or Windows 10's automatic file downloading but am wondering if anyone has any further advice as to how I can remedy this issue?
As of now, I'm stuck with 7,101/12,424 files backed up.
Another confusing detail is that the backup seemed to work perfectly with files in the iCloud Drive folder. Which is also a large folder consiting of (144GB) 64,965 files which are a variety of formats including images and videos. They all seem to have copied perfectly bar 8. Very strange.