HLK OpLocks Test Started Failing for Windows Server 2022 21H2 (build 10.0.20348)

NTDEV
1

There have been zero changes to my HLK test lab VMs between last week and this week. The driver that I’m testing has literally had nothing more than a one line change made to it with a ‘case’ being added to a ‘switch’ block. HLK tests of the previous build were 100% successful last week. HLK tests of the current build are now consistently failing just on Windows Server 2022 21H2 (build 10.0.20348) test clients, and only for the OpLocks tests.

I investigated the log files and noted something very weird regarding the error type & error code message being reported. The following is a copy & paste of the information from the .wtl viewer:

Title Result
Failed
Start Test 7/1/2026 5:40:34.045 AM HelperBreakLegacyL2
Error 7/1/2026 5:40:34.045 AM 08C.1694 : +VAR+SEV2 30 : HelperBreakLegacyL2
File: base\fs\test\shared_libs\stresslog\loggersource\Logger.hxx Line: 283
Error Type:
Error Code: 0x0
Error Text: Error 0x00000000
End Test 7/1/2026 5:40:34.046 AM HelperBreakLegacyL2
Result: Fail
Repro: enhancedoplocks.exe -path i: -all /logpass /logfile FileOplocks-CNTFS.log

Failed
Start Test 7/1/2026 5:42:41.139 AM HelperBreakEnhancedR
Error 7/1/2026 5:42:41.139 AM 08C.1694 : +VAR+SEV2 41 : HelperBreakEnhancedR
File: base\fs\test\shared_libs\stresslog\loggersource\Logger.hxx Line: 283
Error Type:
Error Code: 0x0
Error Text: Error 0x00000000
End Test 7/1/2026 5:42:41.139 AM HelperBreakEnhancedR
Result: Fail
Repro: enhancedoplocks.exe -path i: -all /logpass /logfile FileOplocks-CNTFS.log

Failed
Start Test 7/1/2026 5:45:12.311 AM HelperBreakLegacyL1
Error 7/1/2026 5:45:12.311 AM 08C.1694 : +VAR+SEV2 55 : HelperBreakLegacyL1
File: base\fs\test\shared_libs\stresslog\loggersource\Logger.hxx Line: 283
Error Type:
Error Code: 0x0
Error Text: Error 0x00000000
End Test 7/1/2026 5:45:12.312 AM HelperBreakLegacyL1
Result: Fail
Repro: enhancedoplocks.exe -path i: -all /logpass /logfile FileOplocks-CNTFS.log

Failed
Start Test 7/1/2026 5:47:35.553 AM HelperBreakEnhancedRW
Error 7/1/2026 5:47:35.553 AM 08C.1694 : +VAR+SEV2 66 : HelperBreakEnhancedRW
File: base\fs\test\shared_libs\stresslog\loggersource\Logger.hxx Line: 283
Error Type:
Error Code: 0x0
Error Text: Error 0x00000000
End Test 7/1/2026 5:47:35.553 AM HelperBreakEnhancedRW
Result: Fail
Repro: enhancedoplocks.exe -path i: -all /logpass /logfile FileOplocks-CNTFS.log

Failed
Start Test 7/1/2026 5:49:58.788 AM HelperBreakEnhancedRW
Error 7/1/2026 5:49:58.789 AM 08C.1694 : +VAR+SEV2 77 : HelperBreakEnhancedRW
File: base\fs\test\shared_libs\stresslog\loggersource\Logger.hxx Line: 283
Error Type:
Error Code: 0x0
Error Text: Error 0x00000000
End Test 7/1/2026 5:49:58.789 AM HelperBreakEnhancedRW
Result: Fail
Repro: enhancedoplocks.exe -path i: -all /logpass /logfile FileOplocks-CNTFS.log

Failed
Start Test 7/1/2026 5:52:57.535 AM HelperBreakEnhancedRH
Error 7/1/2026 5:52:57.535 AM 08C.1694 : +VAR+SEV2 86 : HelperBreakEnhancedRH
File: base\fs\test\shared_libs\stresslog\loggersource\Logger.hxx Line: 283
Error Type:
Error Code: 0x0
Error Text: Error 0x00000000
End Test 7/1/2026 5:52:57.536 AM HelperBreakEnhancedRH
Result: Fail
Repro: enhancedoplocks.exe -path i: -all /logpass /logfile FileOplocks-CNTFS.log

Failed
Start Test 7/1/2026 5:55:47.631 AM HelperBreakEnhancedRH
Error 7/1/2026 5:55:47.632 AM 08C.1694 : +VAR+SEV2 104 : HelperBreakEnhancedRH
File: base\fs\test\shared_libs\stresslog\loggersource\Logger.hxx Line: 283
Error Type:
Error Code: 0x0
Error Text: Error 0x00000000
End Test 7/1/2026 5:55:47.632 AM HelperBreakEnhancedRH
Result: Fail
Repro: enhancedoplocks.exe -path i: -all /logpass /logfile FileOplocks-CNTFS.log

Failed
Start Test 7/1/2026 5:57:10.604 AM HelperBreakLegacyBatch
Error 7/1/2026 5:57:10.604 AM 08C.1694 : +VAR+SEV2 123 : HelperBreakLegacyBatch
File: base\fs\test\shared_libs\stresslog\loggersource\Logger.hxx Line: 283
Error Type:
Error Code: 0x0
Error Text: Error 0x00000000
End Test 7/1/2026 5:57:10.605 AM HelperBreakLegacyBatch
Result: Fail
Repro: enhancedoplocks.exe -path i: -all /logpass /logfile FileOplocks-CNTFS.log

Failed
Start Test 7/1/2026 5:58:42.367 AM HelperBreakEnhancedRWH
Error 7/1/2026 5:58:42.367 AM 08C.1694 : +VAR+SEV2 133 : HelperBreakEnhancedRWH
File: base\fs\test\shared_libs\stresslog\loggersource\Logger.hxx Line: 283
Error Type:
Error Code: 0x0
Error Text: Error 0x00000000
End Test 7/1/2026 5:58:42.368 AM HelperBreakEnhancedRWH
Result: Fail
Repro: enhancedoplocks.exe -path i: -all /logpass /logfile FileOplocks-CNTFS.log

Failed
Start Test 7/1/2026 6:00:14.128 AM HelperBreakEnhancedRWH
Error 7/1/2026 6:00:14.128 AM 08C.1694 : +VAR+SEV2 143 : HelperBreakEnhancedRWH
File: base\fs\test\shared_libs\stresslog\loggersource\Logger.hxx Line: 283
Error Type:
Error Code: 0x0
Error Text: Error 0x00000000
End Test 7/1/2026 6:00:14.129 AM HelperBreakEnhancedRWH
Result: Fail
Repro: enhancedoplocks.exe -path i: -all /logpass /logfile FileOplocks-CNTFS.log

I’ve reformatted all of the volumes being used for the testing and ensured that they volume labels, drive letters, file system types, etc., all remain correct. Each test client VM has been rebooted. The error persists and is holding up getting a driver package code-signed by Microsoft.

The driver in question, although it’s technically a mini-filter, does not perform any file system filtering operations and functions purely as a process & thread event collector.

Has anybody else encountered this issue before? A search of existing postings didn’t appear to turn up anything similar and Google Search has not turned up anything helpful, either.

2

Usually my woes with the oplock tests are because the required opkey filter failed to load any chance that’s it?

And have you confirmed that the tests pass without your driver?

3

I’m drawing a total mental blank at the moment regarding the “okpkey” filter. Is that supposed to be specific to the HLK test client itself? I’m assuming fltmc.exe is my friend in this case and that I should be looking for a specific driver to be loaded and bound to the IFS test volumes?

Update:

fltmc reports “Opkey” is loaded at altitude 421111111.1 and has 11 instances.

4

Yup, that’s the one…It was a long shot because I think the failures are a bit more obvious, but it’s what came to mind.

5

Apparently Microsoft is aware of this issue on Windows Server 2022 21H2 as having been caused by a KB update from April 2026 in combination with a subsequent servicing stack update that was released in June of 2026. I double checked the publishing date of the latest HLK filters ‘.cab’ file, which is dated 6/23/2026, and it was newer than the filters I had applied late in April of 2026. After applying the updated HLK filters, the test failures are showing up as a qualified success (e.g. pale green checkmark inside a pale green circle).

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6

Interestingly enough, while performing another round of HLK testing in the same driver using the same VMs, but with the Windows Server 2022 21H2 client VMs having had yet another round of Windows Updates applied, the OpLocks tests once again failed. Again, I checked the HLK site for updated filters, found that the ‘.zip’ archive that I downloaded was different from the previous one which contained mitigations for the previous OpsLock test failures, and applied it to the HLK controller VM associated with those 2 HLK client VMs. With that updated set of filters applied, a re-run of the Opslock tests on those 2 HLK client VMs was once again a qualified success.

The lesson that should be learned with this is don’t cut corners on HLK environment maintenance even if it’s only been a week or two since the previous successful testing run for any given driver regardless of how few or many changes have been made to it. Checking for updated filters and applying them uniformly to all HLK controllers before running any tests should be a part of standard operating procedure. The same applies to keeping HLK client systems fully up to date with Windows Updates being applied routinely so that they aren’t down-level when testing is performed.

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