What is NDProxy?
The genuine NDProxy.sys file is a software component of Microsoft Windows Operating System by Microsoft Corporation.
"NDProxy.sys" is a kernel-mode driver provided by Microsoft that is part of the Windows Operating System, located in "C:\Windows\System32\drivers", which is essential to Windows support of telephone communications via the Telephony API (TAPI). It is responsible for handling kernel-mode Service Provider Interface (SPI) requests generated by NDPTSP from user-mode TAPI requests made by third-party applications or by RAS functions. These SPI requests drive NDProxy's interface in kernel mode (via NDIS) with the NDISWAN driver and a network card's miniport driver with an integrated or separate call manager.
NDProxy stands for NDIS Kernel Mode Proxy driver
NDProxy.sys is a Windows driver. A driver is a small software program that allows your computer to communicate with hardware or connected devices. This means that a driver has direct access to the internals of the operating system, hardware etc.
The free file information forum can help you determine if NDProxy.sys is a Windows system file or if it belongs to an application that you can trust.
Run a free scan to check for NDProxy drivers in need of updating
NDProxy.sys file information
The process known as NDIS Proxy belongs to software Microsoft Windows Operating System by Microsoft (www.microsoft.com).
Description: The original NDProxy.sys is an important part of Windows and rarely causes problems. NDProxy.sys is located in the C:\Windows\System32\drivers folder.
Known file sizes on Windows 10/11/7 are 40,960 bytes (75% of all occurrences) or 49,664 bytes. 
The driver can be started or stopped from Services in the Control Panel or by other programs.
The file is a Windows system file. The program has no visible window. It is a Microsoft signed file. There is no detailed description of this service.
NDProxy.sys appears to be a compressed file.
Therefore the technical security rating is 0% dangerous, however you should also read the user reviews.
Recommended: Identify NDProxy.sys related errors
If NDProxy.sys is located in the C:\Windows\System32 folder, the security rating is 40% dangerous. The file size is 60,416 bytes.
It is not a Windows core file. The program has no visible window.
NDProxy.sys appears to be a compressed file.
Important: Some malware disguises itself as NDProxy.sys, particularly when not located in the C:\Windows\System32\drivers folder. Therefore, you should check the NDProxy.sys process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.
Best practices for resolving NDProxy issues
A clean and tidy computer is the key requirement for avoiding problems with NDProxy. This means running a scan for malware, cleaning your hard drive using 1cleanmgr and 2sfc /scannow, 3uninstalling programs that you no longer need, checking for Autostart programs (using 4msconfig) and enabling Windows' 5Automatic Update. Always remember to perform periodic backups, or at least to set restore points.
Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the 6resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off repairing of your installation or executing the 7DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.
To get your computer running as fast as it did on day one, you can 8reset your PC. Your personal files will remain intact, but any programs you installed will need to be reinstalled.
To help you analyze the NDProxy.sys process on your computer, the following programs have proven to be helpful: ASecurity Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. A good Bantivirus software detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.
Other processes
autoserv.exe ioproduct.exe apdproxy.exe NDProxy.sys knlwrap.exe credentialuibroker.exe lssass.exe arcmonitor.exe systemspawn.exe twcapp.exe findmyfiles.exe [all]
Score
User Comments
not a moron
Jane
Kelso (further information)
Summary: Average user rating of NDProxy.sys: based on 3 votes with 4 user comments. 3 users think NDProxy.sys is essential for Windows or an installed application. One user is not sure about it.