Telephony (tapisrv) Service Defaults in Windows 10

Provides Telephony API (TAPI) support for programs that control telephony devices on the local computer and, through the LAN, on servers that are also running the service.

Default Settings

Startup type: Manual
Display name:Telephony
Service name:tapisrv
Service type:share
Error control:normal
Object:NT AUTHORITY\NetworkService
Path:%SystemRoot%\System32\svchost.exe -k NetworkService -p
Registry key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\tapisrv
  • SeAuditPrivilege
  • SeChangeNotifyPrivilege
  • SeCreateGlobalPrivilege
  • SeImpersonatePrivilege
  • SeIncreaseQuotaPrivilege
  • SeAssignPrimaryTokenPrivilege

Default Behavior

Telephony is a Win32 service. In Windows 10 it is starting only if the user, an application or another service starts it. When the Telephony service is started, it is running as NT AUTHORITY\NetworkService in a shared process of svchost.exe along with other services. If Telephony fails to start, the failure details are being recorded into Event Log. Then Windows 10 will start up and notify the user that the tapisrv service has failed to start due to the error.


Telephony cannot be started under any conditions, if the Remote Procedure Call (RPC) service is disabled.

While Telephony is stopped, the Fax service cannot be launched.

Restore Default Startup Configuration of Telephony

Before you begin doing this, make sure that all the services on which Telephony depends are configured by default and function properly. See the list of dependencies above.

1. Run the Command Prompt as an administrator.

2. Copy the command below, paste it into the command window and press ENTER:

sc config tapisrv start= demand

3. Close the command window and restart the computer.

The tapisrv service is using the tapisrv.dll file that is located in the C:\Windows\System32 directory. If the file is removed or corrupted, read this article to restore its original version from Windows 10 installation media.