Err Msg: The Telephony System Cannot Perform That Function at...

When you try to add or remove a Telephony driver, you may receive the following error message:

This message can occur if you try to add or remove one of the following Telephony drivers using the Telephony tool in Control Panel:

• NDISWAN TAPI Service Provider
• Unimodem Service Provider

This behavior is by design.

You cannot remove these drivers or their associated functionality from your computer. The ability to add and remove Telephony drivers has been provided for Original Equipment Manufacturers (OEMs) and for updates to the Telephony Application Programming Interface (TAPI).