UrBackup Client at idle time it uses one core per 100%


I have a windows client version 2.4.8 at idle time it uses one core per 100%

Could you create a memory dump of the process while this occurrs? (howto: https://support.microsoft.com/en-us/help/931673/how-to-create-a-user-mode-process-dump-file-in-windows )

it always consumes 100% of a single core


link to memory dump.

Thanks! Could you send the client log file as well?

debug.7z (47.9 KB)

Sorry, no hints yet w.r.t. the cause :confused:

Could you capture a bit of what UrBackupClientBackend.exe does with https://docs.microsoft.com/de-de/sysinternals/downloads/procmon and send that as well?

I am experiencing the exact same issue. Windows Client version 2.4.8, Windows 7 64-bit PC.

Logfile.7z (559.4 KB)

Windows 10 x64 1903 18362.418

No hints either. Could be it is caused by ipv6. If you add


to C:\Program files\UrBackup\args.txt and it doesn’t occur that would confirm this.

Well I’ll try. If I restart the service it stops using the CPU at 100% for a while.

After IPv6 is disabled, everything is fine.

1 Like

Same issue here.
I have UrBackup client running for 1 or 2 years and the CPU issue didn’t occur so far.
Problem started just yesterday, UrBackup client was stuck as using a full CPU thread all day long. I wasn’t sure if it was actually working on idle.

Disabling IPv6 resolved the issue.
(and restarting the client backend service)


Could someone create a few memory dumps while the thread is at 100%? (see https://docs.microsoft.com/en-gb/archive/blogs/debugger/what-is-a-dump-and-how-do-i-create-one#to-create-a-dump-using-task-manager how)

Hopefully that shows where it loops…

  • I have two computers having the same problem, both at the same location, same network, almost same windows 10 configuration.
  • debug.log contains many of these entries:
  • WARNING: Parent of file with FRN 30680772461791824 (Name “006D000000050A507278AC03”) with FRN 281474976710685 not found. Searching via MFT as fallback.
  • WARNING: Parent directory not found in MFT. Was probably deleted.
  • the internet access was updated to Deutsche Glasfaser a few months ago which uses ipv6 natively.
  • backup over internet is not configured.
  • This problem only occured recently.
  • It appeared only file backups were affected by this (verified by seeing that an image backup was made after the problem was reported to me)
  • Updating the server to the latest version did not help.
  • A fresh reinstallation, making sure there were no files left in installation directoy before installation results in the same symptoms.
  • Disabling ipv6 via args.txt helped making the 100% load go away.

I will send you the memory dump via email.

I cannot send you any email:

info@infscape.com: host mail.infscape.com[] said: 550 5.1.1
info@infscape.com: Recipient address rejected: User unknown in virtual
mailbox table (in reply to RCPT TO command)

Disabling ipv6 via args.txt did not fully resolve the problem. No backup could be done.
Disabling ipv6 on the network adapter (and restoring args.txt) helped. Backups are working normally again.

Here is one dump.

Edit: Removed. Thanks. got it.

Try bugreports@urbackup.org . Thanks!

Can’t see a problem yet :confused:

What would also be helpful would be a procmon log of the UrBackupClientBackend.exe process. Please restart the service while procmon is logging, so it logs the startup: