Slow Upload Speed on Win11

I

il_6

Bit poster
Running Win 11 ARM on M1 MBA.. randomly (maybe once every day or two), upload speed slows to a crawl in VM. No issue with download speed. 80 down/~0.15 up speedtest. 80/80 in Mac. Using shared network.

Not sure if this is a Windows 11 or Parallels NIC driver issue. The fix is simply to disable and reenable the NIC (in Windows). Haven't tried iPerf or anything to confirm it's both LAN and WAN, but would I assume so. Kind of hard to definitively pin down when it happens, but it SEEMS to occur after Windows or the Mac has slept. Event viewer shows repeated errors below until it's fixed, maybe Netbios related. I will try to disable Netbios but anyone have any ideas?

The server could not bind to the transport \Device\NetBT_Tcpip_xxx because another computer on the network has the same name. The server could not start.
 
I have the same issue!
Latest Windows 11 Dev build
Latest Parallels Desktop

Restarting VM works for a brief while.
After that 14 Mb/s down to 16 kb/s.
 
Yep. Try simply disabling and re-enabling the Parallels network adapter - works every time for me. Disabling NetBIOS didn't make a difference other than to suppress the event log errors.
It seems to be related to sleep or suspend (either on Win or Mac, not sure), happens most often when I step away for lunch. I manage a number of Win 11 endpoints and haven't seen the behavior on any of them, it definitely seems to be a Parallels (Nic?) specific issue.
 
il_6 said:
It seems to be related to sleep or suspend (either on Win or Mac, not sure), happens most often when I step away for lunch. I manage a number of Win 11 endpoints and haven't seen the behavior on any of them, it definitely seems to be a Parallels (Nic?) specific issue.
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It seems like a related issue where my Win 11 VM all of a sudden keep going to the lock screen requiring me to put the PIN/Password. It seems like this speed issue and lock screen issue happened around the same time: Windows 11 login loop
 
Hi guy, I have the absolute same issue! Latest Windows 11 Dev build and latest Parallels Desktop -> no time to investigate. If any body was able to solve this issue, please let me know how to solve.
 
StephanW8 said:
Hi guy, I have the absolute same issue! Latest Windows 11 Dev build and latest Parallels Desktop -> no time to investigate. If any body was able to solve this issue, please let me know how to solve.
Click to expand...
No permanent fix but disable/enable NIC restores the upload speed until the next sleep/pause. Running the semi-official ISO build here, so it's not isolated to dev builds. It's definitely annoying.
I suspect more users are having this issue without noticing, since download speed is unaffected. Also prl_naptd process goes 100% cpu occasionally, not sure if it is related or not (I usually only notice when battery drains quickly).
 
Same issue: outbound network traffic from VM is incredibly slow. Internet upload/down speeds on new host MBP M1 (and most other computers in my house) 150Mbs upload, 6 download. On my Windows 11 VM (still not activated) 150 download, 0.04 download! Under VM configuration, devices, network, I've disconnected, reconnected, turned conditioning off/on, changed to default adapter, wifi adapter, and nothing seems to make much difference.
 
Found a fix: changed "Configure for" from "Software Development" to "Productivity".
I discovered this after creating a brand new, default windows 11 VM. Ran a quick speed test on the new VM and it matched my host MacBook Pro. My original VM was intentionally set to "Software Development" because I'm a Windows/SQL dev. I'd be curious if this fixes it for others. I logged a ticket with Parallel support and will follow up with this group.
 
Same issue, very frustrating as I use Dragon dictate which requires decent upload. Found solution: go to Windows 11>Settings> GENERAL tab. Select the CONFIGURE FOR and choose GAMES ONLY. it allows maximal use of resources.
 
I encountered this issue for this first time today and can confirm that disabling and re-enabling the Parallels VirtIO Ethernet Adapter resolved the issue (at least temporarily). I'm on an M1 MBP running the latest Windows 11 Dev build as my Guest OS.
 
hello,
Same issue since few days ...
Nothing changed on my configuration and went from the same upload than the host to something lower than 0,5 mb/s ...
 
GregS34 said:
Found a fix: changed "Configure for" from "Software Development" to "Productivity".
I discovered this after creating a brand new, default windows 11 VM. Ran a quick speed test on the new VM and it matched my host MacBook Pro. My original VM was intentionally set to "Software Development" because I'm a Windows/SQL dev. I'd be curious if this fixes it for others. I logged a ticket with Parallel support and will follow up with this group.
Click to expand...
Checking back to say this did not turn into a fix. The support got back to me with the fix below - reinstall tools and use a bridged mode connection. I just did that and it seems to be fixed... for now.

Please try the below troubleshooting steps to resolve your network issue. 1.Reinstall Parallels tools by follow the below KB Article link. https://kb.parallels.com/4841 2.Change the network setting to Bridge Network by following the below link. https://kb.parallels.com/8978 If you are changing the network to Bridge mode then select the settings as WiFi if your Mac is using WiFi. If your Mac is using Ethernet then select Ethernet. If both are not working then select Default.
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I have also the same problem, MacBook AIR M1 Win 11 dev, latest everything, weekly Parallels Tools needs to be reinstalled to fix the really slow (0.2Mbps in Windows Task Manager) upload speed.
 
Not resolved in the the latest update (51548), FYI
For those who keep reinstalling Parallels Tools, make sure you try NIC disable/enable first. Resolves the issue every time for me immediately (of course, only until the next sleep/pause cycle..)
 
il_6 said:
Running Win 11 ARM on M1 MBA.. randomly (maybe once every day or two), upload speed slows to a crawl in VM. No issue with download speed. 80 down/~0.15 up speedtest. 80/80 in Mac. Using shared network.

Not sure if this is a Windows 11 or Parallels NIC driver issue. The fix is simply to disable and reenable the NIC (in Windows). Haven't tried iPerf or anything to confirm it's both LAN and WAN, but would I assume so. Kind of hard to definitively pin down when it happens, but it SEEMS to occur after Windows or the Mac has slept. Event viewer shows repeated errors below until it's fixed, maybe Netbios related. I will try to disable Netbios but anyone have any ideas?

The server could not bind to the transport \Device\NetBT_Tcpip_xxx because another computer on the network has the same name. The server could not start.
Click to expand...
Create shortcut on Windows 11 desktop to Parallels VirtIO Ethernet Adapter. Click on disable and then enable. Parallels engineers are aware of issue and it should be fixed in next release.
 
ROBERTM78 said:
Create shortcut on Windows 11 desktop to Parallels VirtIO Ethernet Adapter. Click on disable and then enable. Parallels engineers are aware of issue and it should be fixed in next release.
Click to expand...
Thank you! This works great. Hope they do fix this soon.
 
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