Add documentation around error 0xc0000142 on windows

Author: NHAS

README.md

@@ -68,7 +68,9 @@ https://github.com/user-attachments/assets/11dc8d14-59f1-4bdd-9503-b70f8a0d2db1
     - [Fileless execution (Clients support dynamically downloading executables to execute as shell)](#fileless-execution-clients-support-dynamically-downloading-executables-to-execute-as-shell)
       - [Supported URI Schemes](#supported-uri-schemes)
 - [Help](#help)
-  - [Windows and SFTP](#windows-and-sftp)
+  - [Windows](#windows-help)
+    - [SFTP](#windows-and-sftp)
+    - [Error ]()
   - [Server started with `--insecure` still has `Failed to handshake`](#server-started-with---insecure-still-has-failed-to-handshake)
   - [Foreground vs Background](#foreground-vs-background)
 - [Donations, Support, or Giving Back](#donations-support-or-giving-back)
@@ -433,7 +435,9 @@ Both of these methods will opportunistically use [memfd](https://man7.org/linux/
 
 # Help
 
-## Windows and SFTP
+## Windows
+
+### SFTP
 
 Due to the limitations of SFTP (or rather the library Im using for it). Paths need a little more effort on windows.
 
@@ -443,6 +447,40 @@ sftp -r -J your.rssh.server.internal:3232 test-pc.user.test-pc:'/C:/Windows/syst
 
 Note the `/` before the starting character.
 
+## Session spawn errors (0xc0000142)
+
+Under some execution circumstances connecting to an RSSH client on windows may fail with no error. 
+
+```sh
+catcher$ connect windows-system
+Session has terminated.
+```
+
+Client logs:
+```sh
+2025/08/24 18:25:39 [client] INFO session.go:52 func16() : Session got request: "shell"
+2025/08/24 18:25:39 [client] INFO shell_windows.go:137 runWithConpty() : New process with pid 3427 spawned
+2025/08/24 18:25:39 [client] INFO session.go:122 func16() : Session disconnected
+```
+
+There are two common causes for this, the first being antivirus has killed the spawned powershell, and the other `0xc0000142` is when the resulting process does not have the permissions to access the Windows Station or Desktop [source](https://stackoverflow.com/questions/677874/starting-a-process-with-credentials-from-a-windows-service/30687230#30687230).
+
+
+To determine which is causing this issue, execute any command without a pty: 
+
+```sh
+ssh -J rssh windows-system cmd /c dir                                
+exit status 0xc0000142
+```
+
+If you see the `0xc0000142` error code try starting `CMD.exe` and force allocating a pty (`-t`):
+
+```sh
+ssh -t -J rssh windows-system CMD.exe
+```
+
+This should start an interactive shell.
+
 ## Server started with `--insecure` still has `Failed to handshake`
 
 If the client binary was generated with the `link` command this client has the server public key fingerprint baked in by default. If you lose your server private key, the clients will no longer be able to connect.