This means that somehow your "registration data" has been lost.
For using VMware Player you don't need to register using a license key, but it asks for an email address instead.
So while not obvious registration data, let's just call it that to keep things simple.
No, it isn't supposed to happen.
I also don't think it has anything to do with malware.
The file (or registry location) that holds the registration data gets initialized or rolled back somehow.
This might be due to windows trying to fix something on your behalf or some tool that you are running on your host.
Sorry don't know where this data is kept and not even sure that VMware would like it to be shared here if I did know.
Wil| Author of Vimalin. The virtual machine Backup app for VMware Desktop Products
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