Big Sur, Time Machine, SMB, umount, and Safari networking issue

I'm experiencing this same problem. I tried to upgrade to the 11.1 beta (big sur developer beta) and the problem, unfortunately, got worse. Instead of just hanging network calls for a few apps or take up CPU cycles, the entire computer becomes unusable. All devices (bluetooth or USB) are unresponsive and I'm forced to restart the computer for it to come back.

This thread NEEDS to get more Apple Support attention. I have to pick between no more TimeMachine backups and downgrading my computer.

Same problem here. Plus to sampling the umount process I also looked at dmesg. No debug info ever. Apple must have broken something in the kernel, but I think the Big Sur kernel is still not released so the only hope is Apple seeing this thread...

I'm also facing this issue on a MacBook Pro (15-inch, 2016) when backing up to an AFP-share on my NAS.

I was hoping that the upgrade to macOS 11.1 would fix it, but (as mentioned by others) It's still not working.

Exact same Problems (Timemachine, Freezing Network/ Unmount/ Safari/ Chrome!! SMB)

MacBook Pro (16 Zoll, 2019) Big Sur 11.1

I really new i should have wait. I always wait at about 6 months with new Updates.

Apple is so expensive and makes us to beta testers, really bad. Same story since ever....

We have a few Machines here (Minis, Macbook Pros, etc.).... Same Problems

Finally I have found other people having the same issue as me! Has there been a fix yet? Is there anything that can be done, other than disabling automatic backups? This is really frustrating and is killing my daily workflows.

Exact same issues as everyone has mentioned. I'm backing up to a QNAP device, so I would say this isn't specifically related to Synology.

MBP 16" 2019, Big Sur 11.1

I will try that now. Since finding this thread I have disabled automatic backups but it has only been 20 minutes since I've done that. I may leave them off for a few days to confirm that cures it, then try your suggestion. Thank you Joegeorge!

Same problem.

Safari won't connect to any URLs. When I check Activity monitor the "unmount" process is listed as using 100% CPU. Oddly, it occasionally drops to exactly 99.9% and then goes back to 100%.

While Safari will not go to any URLs while this is going on, Firefox will — e.g. it seems to affect Safari in particular.

My backups are over wireless (using a Google mesh system) to a Mac mini with an external drive holding backups for several computers in our home. The problem was originally with a relatively new MacBook Air, but another computer on the network has developed the same problem since updating to Big Sur. That one is a recent 8-core iMac, also on the wireless network.

Disabling Time Machine backups is really not an option. I have been using SuperDuper backups along with Time Machine (I'm a paranoid backer upper) but Big Sur also created problems that now prevent SuperDuper from backing up the boot volume.

This is a pretty serious combination of problems at this point.

One more data point regarding the issue on my setups.

Let's say that I have loaded a page on Twitter in Safari before the problem occurs. I can continue to load other pages on Twitter (or another URL) while unmount is taking 100% (at least this is true on one of my computers) but if I try to go to a different URL it will not work.

Two replies to the thread.

First, I'm backing up over 8TB via a wireless network, so rebuilding the backup completely is a major, very slow operation. I just did that a couple of months ago (for a different reason) so I'm not very interested in that option.

In some cases I have been able to quit the process in Activity Monitor, but on other occasions that process would not quit. I haven't tried that again recently, but I'll give it another go.

I'm still having the problem, even after doing the most recent Big Sur updates.

It doesn't "crash."

What happens is that Safari (seemingly the only application affected, oddly enough) won't open any new URLs while the unmount process is running. "Unmount" seems to be connected with Time Machine running a backup update over my network to a remote Mac.

The hangup continues for several minutes after the backup appears to have concluded. It also does not seem to happen every time.

I'm not taking the days and days to rebuild the backup from scratch because I keep thinking that one of the incremental updates to Mac OS Big Sur will address this problem.

I have the same problem.

I have it on safari and on google chrome.

I tried the chrome beta channel but not a solution

I have now disabled the time machine backups (triggered by this thread)

I don't think the problem lies with Synology, I think the bug is in Big Sur.

Are there people out here that have this problem with a non-synology network-product?

Just filed a radar (FB8923253) with some info and some sysdiagnose when the issue occurs.

Actually it is impacting my Macbook 12''