Parallels 20 & 26 hangs with "starting..." message and/or repeated requests to reboot

I have a 2025 Macbook Pro M4 Max running Sequoia current version. I have tried starting Parallels 20 and by mistake, bought Parallels 26 but neither will get past the starting... splash screen. I get the same behaviour when clicking on the virtual machine or the app icon. The screen appears for a minute or so and then quits without any warning other than the occasional message to restart and then the splash screen reappears and the loop goes on.
What to do?
According to this site, I am eligible for email support on both products, but unsurprisingly, there's no email address anywhere. There's an option for a new support ticket but that just goes in a loop back to the support entry page.
I'm supposedly eligible for phone support but there's no phone option listed anywhere that I can see.
I know this is standard practice on many "support" sites and I did not expect much from Parallels but they have exceeded my low expectations.

 

This is happening to me too now, ever since updating it. I tried uninstall/reinstall multiple reboots, but it just keeps doing the same thing. Just sits on starting.

 

After a tedious series of emails from support with me emailing back gigabytes of data, I had a long session with a Parallels tech via Logmein. What a mess trying to remove that from my system! The result of this was me asking for a refund on Parallels 26 but at the end, I don't understand what the problem is, other than that I have what they call a "standard" edition with a permanent licence and if I want this to work with Windows 10, then I need to subscribe to a business edition or something else more expensive. Which I am not about to do.

Why this doesn't make sense is that both Windows 7 and 10 VPMs worked fine on my previous laptop which was an M1 MacBook Pro. I changed the computer to an M4 which shouldn't cause a problem, reinstalled Parallels 20 and then the problems started. These VMs work fine on an Intel Mac.

It's notable that in all the spam emails from Parallels stating that the new version will be 80% faster etc etc. they never mention incompatibilities as noted below. Anyway, the VMs worked on M chips with P20 and ought to work on on M1 as well as M4 chips. The only thing I can think is that at some point, Parallels have changed the "emulation" to not work on the standard version. I fail to understand this because I thought I was buying an emulator in the first place.

This is the reply:

a) The session went as follows:

1. We determined that the Windows 10 machine was an x64 virtual machine, meaning it was created on an Intel Processor Mac.
2. You are currently on an M4 Mac which has an arm64 processor. Due to this architecture difference the original x64 Windows 10 cannot run directly on it.
3. Since you have a Standard license, it does not give you the emulation feature of Parallels Desktop. So we provided you with a 5 Day temporary Pro license key and were able to start the Windows 10 machine via emulation and confirm it works.
4. You also requested for a refund for the Parallels Desktop 26 Permanent upgrade license that you purchased.

b) So just to re-iterate:

1. At the moment you are able to run the Windows 10 via emulation technology since the Temporary Pro license is being used for Parallels Desktop 26.
2. You have mentioned that you will switch back to version 20. But please note that when you switch back the license back to the version 20 Standard, note that you will not be able to use the Windows 10 but you can create a Windows 11 virtual machine and use that accordingly.

Which doesn't explain why everything worked fine on P20 and an M1 MacBook unless it's a grab for a subscription licence.