Add new TSG for known issue with Test-AzStackHciARBStack

Author: SebasRG23

TSG/Update/README.md

@@ -30,4 +30,5 @@
 * [Troubleshooting MSI Does Not Have Access to Subscription](../EnvironmentValidator/Troubleshooting-MSI-Does-Not-Have-Access-To-Subscription.md)
 * [2510 Update fails at CauPostVersionCheck](./CauPostVersionCheck-2510-23H2.md)
 * [Update preparation fails with 'Could not find part of the path' after 24H2 upgrade](./Update-preparation-fails-Could-not-find-part-of-the-file-path.md)
-* [2509 | Update Service terminated repeatedly by ALM due to high memory usage](./Update-Service-terminated-repeatedly-by-ALM.md)
+* [2509 | Update Service terminated repeatedly by ALM due to high memory usage](./Update-Service-terminated-repeatedly-by-ALM.md)
+* [Test-AzStackHciARBStack: Fails on Non-Numeric Az CLI Extension Versions](./Test-AzStackHciARBStack-NonNumericAzCLIExtensionVersions.md)

TSG/Update/Test-AzStackHciARBStack-NonNumericAzCLIExtensionVersions.md

@@ -0,0 +1,20 @@
+
+# Test-AzStackHciARBStack Fails on Non-Numeric Az CLI Extension Versions
+
+## Symptoms
+- Environment Validator fails in the Test-AzStackHciARBStack function with an error related to parsing az cli extension versions containing non-numeric characters (e.g., "1.0.0b1").
+- Error message similar to:
+   Exception occurred (Test-AzStackHciARBStack): Cannot convert value "1.0.0b1" to type "System.Version". Error: "Input string was not in a correct format."
+
+
+## Summary
+A bug in the Environment Validator's Test-AzStackHciARBStack function causes it to fail when az cli extensions have non-numeric version strings (such as beta versions like "1.0.0b1").
+
+**Applies to:**
+- Azure Stack HCI releases 2601, 2602, and 2603 only.
+- **Note:** From release 2604 onwards, the validator has been reworked and no longer checks extension versions in this way.
+
+## Mitigation
+Refer to the main TSG for incompatible az cli extensions for mitigation steps:
+
+- [UpdatePrerequisites Failure: Remove Incompatible Extensions](./UpdatePrerequisites-Failure-Remove-Incompatible-Extensions.md)