Windows 10 Insider Preview Fast Build 19541 - January 8  

To resolve issue on VMWare or Parallels change hard disk type to SATA from SCSI, reboot and then install update.

cocotropico said:

I had success installing 19541 on VMWare by putting the virtual HDD in a SATA controller instead of the SCSI controller (which VMWare choose by default when creating a VM by the recommanded way in the wizard)

Thanks for that. For a clean install, that works, as you did it. But, () this is an update of an existing guest machine, and no can do, it's locked into SATA. Least not that I'm aware of. If you have a trick to "convert" it somehow, I'm all ears!

You can just change the hard disk type by shutting down vm then change disk type from scsi to SATA and boot up and upgrade, no need for converting or clean install.

cocotropico said:

You can reassign the same virtual hdd when creating a new one on the VM settings, just select SATA instead of SCSI. Then delete the old one. Restart VM and update to 19541

I'll have to look all that up when not so semi-braindead. You're a night owl, I crash by 9pm. I may be back to you for instructions or point me to something. I'd love to try it.

First, stop your virtual machine.
Navigate to the left pane and click Edit virtual machine settings.
Click the Add button at the bottom of the Virtual Machine Settings page.
A new window Add Hardware Wizard will open on your screen.
Select New Hard Disk > SATA and click on Use an existing virtual machine.
Use an existing virtual machine
Now browse your .vmdk file and click the Finish button.

f14tomcat said:

Thanks for that. For a clean install, that works, as you did it. But, () this is an update of an existing guest machine, and no can do, it's locked into SATA. Least not that I'm aware of. If you have a trick to "convert" it somehow, I'm all ears!

There is no trick but you can probably change the hard disk type (assuming you have enough free disk space) by working with vdiskmanager. I have never done this however, nor even tried. Using Virtual Disk Manager
Good luck.