Parallels VM - screen res too high, can disable custom scaling

I have a new installation of Windows 10 Pro build 15063.296 running on a Macbook Pro with an external Dell 2416D monitor.

Windows screen resolution is defaulting to 5120 X 2750 which exceeds my monitor's maximum resolution of 2560 X 1440. If I change the resolution in 'display settings', it changes the window size but does not change the scaling.

Display Settings > Scale and Layout says a custom scale factor is set. If I try to turn it off and sign out, the settings persist when I log back in.

How can I resolve? Is this a Windows problem or a Parallels problem?

Hi there
I'm not too sure about parallels but if it follows the usual conventions of running Virtual machines there ought to be some setting in either the config file to specify the resolution of the virtual machine or something in the menu VM like view-->option file "Auto fit Guest" etc.

I'm using a Windows VM on a Linux machine with VMWARE workstation which works perfectly so I can't give you the various settings on parallels - but try them.

Look also in the virtual machine config file - there should be one even in parallels and see if there are any settings or google for parallels config file.

Here's an extract of mine -- the file is (on VMware) a .vmx type file but you should see something like this :

#!/usr/bin/vmware
.encoding = "UTF-8"
config.version = "8"
virtualHW.version = "12"
scsi0.present = "TRUE"
scsi0.virtualDev = "lsisas1068"
sata0.present = "TRUE"
memsize = "2048"
mem.hotadd = "TRUE"
scsi0:0.present = "TRUE"
scsi0:0.fileName = "Windows 10 x64.vmdk"
sata0:1.present = "TRUE"
sata0:1.fileName = "/mnt/DV2/Macrium VM/Rescue.iso"
sata0:1.deviceType = "cdrom-image"
ethernet0.present = "TRUE"
ethernet0.virtualDev = "e1000e"
ethernet0.wakeOnPcktRcv = "FALSE"
ethernet0.addressType = "generated"
usb.present = "TRUE"
ehci.present = "TRUE"
ehci.pciSlotNumber = "34"
usb_xhci.present = "TRUE"
sound.present = "TRUE"
sound.startConnected = "FALSE"
sound.virtualDev = "hdaudio"
sound.fileName = "-1"
sound.autodetect = "TRUE"
mks.enable3d = "TRUE"
svga.graphicsMemoryKB = "1048576"
pciBridge0.present = "TRUE"
pciBridge4.present = "TRUE"
pciBridge4.virtualDev = "pcieRootPort"

etc etc ...

Cheers
jimbo