Prolific shows "THIS IS NOT PROLIFIC PL2303" in Device Manager

Devices with the PL-2303 TA Chipset are no longer supported and marked as End Of Life, but you may come across sites that have updated to Windows 11 with them in use. 

UPDATE: Windows 10 also will attempt to update the driver which breaks it.

When this is the case, the Prolific USB-to-Serial driver will rename itself, as seen below.

THIS IS NOT PROLIFIC PL2303.  PLEASE CONTACT YOUR SUPPLIER.

Fix:

In order for these adapters to function on Windows 11, you must install a particular version of the driver attached below. Same driver version recommended for Windows 10 as well.  

Device Manager - right-click on the broken driver and Uninstall (tick the "remove driver" checkbox).

Install the v1200 driver package as attached.  Reboot.

PL2303_Prolific_DriverInstaller_v1200

Sometimes, it won't accept the driver properly (or the driver does install but printer still throws up an error) - in that case Browse manually and get a list of Available drivers.  Select the 2018 or earlier driver.  Reboot.

If Windows attempts to update the driver again - within device manager there is an option to "Roll-back driver".  Select "my apps don't work with the driver" option.  Select the 2018 or earlier driver.  

Note:  After all this the COM PORT number may have changed.  Double check and update in Idealpos if necessary.

Additional Fix:

You may also want to disable driver updates via Windows Update using Group Policy.

Win key + R - in the Run box enter gpedit.msc, and hit OK. This will open the Local Group Policy Editor.

Use the left pane to navigate to Computer Configuration > Administrative Templates > Windows Components > Windows Update > Manage updates offered from Windows Update.)

Double-click the Do not include drivers with Windows Updates policy and enable it.