It sounds as though it is trying to read the state of the WDM Feature from the admin account (which they automatically disabled in build 96) instead of the limited account.
Surely there must be a better solution than "run MC on your admin account and activate it".
That is absolutely, exactly what it is doing, and it is because of the fundamental nature of user accounts on Windows. Please, just try what Hendrik said:
You could probably fix it by running MC itself as Admin, and then changing the setting there.
He was
not saying "you have to use MC as an administrative user". He was saying: Run MC
once as the administrative user which you must already have and which you use to install the updates each time. Run MC once, not the installer but MC itself, as
that user, and go into
Tools > Options > Settings > Features and turn the thing on
there.
I already explained this up above and Hendrik confirmed, I thought, but I'll try again. The settings MC uses which are accessible in Tools > Options are stored in the HKCU registry hive. The setting itself is here:
HKEY_CURRENT_USER\Software\JRiver\Media Center 20\Features\DriverWDMThe administrative user you use to install MC
cannot access the
limited user's HKCU registry hive. It can only see its own. You turn it on on your limited user account and this key happily changes to a 1. For that user.
The default setting for MC is to have the WDM Driver disabled, so the administrative user's DriverWDM key is set to 0. The second you validate against that UAC Run As prompt to run
the installer (not the one-off install that happens when you activate the setting, the installer you run
next time you run an update) only "sees" its own settings. These settings say the WDM Driver feature is
disabled. So, as far as the installer is concerned, it
is turned off, regardless of what the HKCU registry key for your limited user's account says, because it can't see that setting.
So, fixing this is drop-dead simple. Open MC one time and make the setting
not be disabled anymore. Close MC. There done.
There's really no other choice for software on Windows. The only other part of the registry both the Administrative and the Limited user can see, that would make sense to use, would be HKLM. But,
I'll quote:
Write Registry Virtualization
If the caller does not have write access to a key and attempts to write a value to it or create a subkey, the value is written to the virtual store.
For example, if a limited user attempts to write a value to the following key: HKEY_LOCAL_MACHINE\Software\AppKey1, virtualization redirects the write operation to HKEY_USERS\<User SID>_Classes\VirtualStore\Machine\Software\AppKey1.
So, the limited user cannot write a setting to the registry which your administrative user can see. It also, for the record, can't write to the Program Files directory either, so they can't even just abandon the whole registry setting system they've been using for decades for this one feature and write out an INI file in their install directory. Is there some crazy way they could rebuild the whole settings system for this one feature and make it work? Maybe, but suck it up and run it once as the admin user and check the stupid box.