Windows Process Activation Service Error 2:The system cannot find the file specified

I have had this problem twice after a windows update. The issue seems to be, that windows adds an incorrect parameter to the WAS service startup parameters. I fixed the issue using the following steps:

• Start regedit (just type it into start)
• Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WAS\Parameters
• Delete the NanoSetup variable. This variable is preventing WAS from starting
• Start the WAS service using task manager or by typing "net start WAS" in Command Prompt
• Start the W3SVC service the same way
• You can now start your website in IIS again

I had the same problem and nothing in here was the solution for me for a long time. So i rolled back windows also. Today i found the solution working for me - Navigate to:

C:\Users\All Users\Application Data\Microsoft\Crypto\RSA\MachineKeys\

find these 3 Key-files...

d6d986f09a1ee04e24c949879fdb506c_*

76944fb33636aeddb9590521c2e8815a_*

6de9cb26d2b98c01ec4e9e8b34824aa2_*

... then in Security-Settings:

• first, you have to set your User as OWNER

• close Properties Dialog - and open again

• Then in ACL set "full controll" for SYSTEM

After that: WPA can be started...

Hope this helps; see also thread here: https://social.technet.microsoft.com/Forums/en-US/315841e1-b8b2-4084-8224-580ef3d13420/upgrade-to-windows-10-1709-iis-fails?forum=win10itprosetup

I had this same problem after installing the Windows 10 1909 update and the nanosetup variable was NOT in the registry. I ended up doing a variation of Sascha's fix.

I took ownership and gave administrators full control of the MachineKeys folder in C:\ProgramData\Microsoft\Crypto\RSA. Then I removed the 3 files in Machinekeys that begin with:

d6d986f09a1ee04e24c949879fdb506c_*

76944fb33636aeddb9590521c2e8815a_*

6de9cb26d2b98c01ec4e9e8b34824aa2_*

The Windows Process Activation Service (WAS) started as expected.