Win 10 Upgrade gives black screen, need help.

[PeteScR]

I am running Win 10 on my iMac using Parallels 14. The latest Win 10 upgrade resulted in a flickering screen. The advice in the pop up said increase graphics memory to 512Mb. I stopped the virtual machine and then changed the drop down selection in control centre to 512Mb. On restart the Windows screen went black. I managed to get back in and stop the VM and reset the display memory to Auto for Retina. On restart I still have a black screen where Windows should be. The Mac applications are running OK. I have tried everything else I know but no joy. I am afraid that I might screw up the Mac altogether if I carry on blindly changing settings. Anyone got a fix for this scenario?

Pete

[ferrarr]

Can you provide basic information like;

Which Mac (OS version, Mac model, specs & year) are you using?
Which virtual app are you using?
Can you allocate more memory than just 512, maybe 1GB (1024mb) or 1.5GB (1536mb)? Does that help?

[Raz0rEdge]

What is your Memory setting under CPU & Memory, the Graphics is uses "system" memory which comes from this bigger pool. You should allocate a minimum of 2048 MB (2GB) to the machine and leave the Graphics memory as Auto to steal what it needs from that 2GB. If you are having graphics issues, bump up the system memory to 4096 MB (4GB).

@Bob, the OP is using Parallels, which is also the app that I'm using. Just upgraded to Parallels 15 today and running Windows 10.

[PeteScR]

Can you provide basic information like;

Which Mac (OS version, Mac model, specs & year) are you using?
Which virtual app are you using?
Can you allocate more memory than just 512, maybe 1GB (1024mb) or 1.5GB (1536mb)? Does that help?

Thanks for the reply. I have a 27" iMac that is only 6 months old, running Mojave 10.4.6. I have a 1T SSD and 32GB of RAM.
I am running Parallels 14 and Windows 10, the latest upgrade.

I have the Display Graphics set to Auto as that is recommended. My CPU/Memory allocation is as shown on the attachment at 2048MB.

Its still the same.

Pete

[PeteScR]

What is your Memory setting under CPU & Memory, the Graphics is uses "system" memory which comes from this bigger pool. You should allocate a minimum of 2048 MB (2GB) to the machine and leave the Graphics memory as Auto to steal what it needs from that 2GB. If you are having graphics issues, bump up the system memory to 4096 MB (4GB).

@Bob, the OP is using Parallels, which is also the app that I'm using. Just upgraded to Parallels 15 today and running Windows 10.

Thanks for the reply. I have bumped the CPU/Memory value up to 4GB and no difference

Pete

[Raz0rEdge]

Was that a Windows 10 update or upgrade. Very different things. If just an update, these don't mess with the Parallels Toolbox for Windows that have been installed on Windows to give it access to all the virtual devices (GPU, Network, Sound, blah blah). If an upgrade, it is likely the tools were removed and you will need to re-install the toolbox. You can do that by clicking on the name of the VM in the menu bar and choosing Install Parallels Toolbox for Windows from there. Since this is an "automatic" thing that doesn't require you to do anything in Windows AND something that will restart the VM about 2 mins after the installation is done, it's OK if you are staring at a black screen through this process.

So while the update should've left the toolbox alone, I would suggest you do a re-install anyway (it won't hurt anything) and see if things begin to work after the restart.

[PeteScR]

Was that a Windows 10 update or upgrade. Very different things. If just an update, these don't mess with the Parallels Toolbox for Windows that have been installed on Windows to give it access to all the virtual devices (GPU, Network, Sound, blah blah). If an upgrade, it is likely the tools were removed and you will need to re-install the toolbox. You can do that by clicking on the name of the VM in the menu bar and choosing Install Parallels Toolbox for Windows from there. Since this is an "automatic" thing that doesn't require you to do anything in Windows AND something that will restart the VM about 2 mins after the installation is done, it's OK if you are staring at a black screen through this process.

So while the update should've left the toolbox alone, I would suggest you do a re-install anyway (it won't hurt anything) and see if things begin to work after the restart.

Apologies for the confusion, it was an update. I hadn't started it for a while and when I did it said there were updates and started installing them. When it was finished that's when the blinking/black screen happened. I will have a look at the toolbox status
Thanks
Pete

[Raz0rEdge]

Apologies for the confusion, it was an update. I hadn't started it for a while and when I did it said there were updates and started installing them. When it was finished that's when the blinking/black screen happened. I will have a look at the toolbox status
Thanks
Pete

I also hadn't started my VM of Windows 10 for a month or so and when I did this morning, I was bombarded with about half a dozen updates that required a couple of restarts. In the midst of that I also upgraded Parallels from 14 to 15 which required the toolbox re-install and I didn't see any flickering or issues with my installation.

[PeteScR]

Was that a Windows 10 update or upgrade. Very different things. If just an update, these don't mess with the Parallels Toolbox for Windows that have been installed on Windows to give it access to all the virtual devices (GPU, Network, Sound, blah blah). If an upgrade, it is likely the tools were removed and you will need to re-install the toolbox. You can do that by clicking on the name of the VM in the menu bar and choosing Install Parallels Toolbox for Windows from there. Since this is an "automatic" thing that doesn't require you to do anything in Windows AND something that will restart the VM about 2 mins after the installation is done, it's OK if you are staring at a black screen through this process.

So while the update should've left the toolbox alone, I would suggest you do a re-install anyway (it won't hurt anything) and see if things begin to work after the restart.

Its strange, I reinstalled the Toolbox and it is asking me to pay or input authorisation code. I'll need to go and dig it out now

Pete

[PeteScR]

I have reinstated Toolbox now so will give it a go.

Pete