# KB5087545 - CBS relevant error lines for MS Q&A post


## 1. KB5087545 installation attempt - start

```text
71188: 2026-05-26 07:26:01, Info                  CBS    Exec: Processing started.  Client: UpdateAgentLCU, Session: 31255760_562088373, Package: Package_for_RollupFix~31bf3856ad364e35~amd64~~20348.5139.1.14, Identifier: KB5087545
71213: 2026-05-26 07:26:01, Info                  CBS    Exec: Extracting package: Package_for_RollupFix~31bf3856ad364e35~amd64~~20348.5139.1.14
71131: 2026-05-26 07:25:57, Info                  CBS    ActionList: Adding package: \\?\C:\Windows\SoftwareDistribution\Download\03964adf9da69748b586449c281feaf9\Windows10.0-KB5087545-x64.cab
71215: 2026-05-26 07:26:01, Info                  CBS    Extracting all files from cabinet \\?\C:\Windows\SoftwareDistribution\Download\03964adf9da69748b586449c281feaf9\Windows10.0-KB5087545-x64.cab
71230: 2026-05-26 07:26:02, Info                  CBS    Extracting all files from cabinet \\?\C:\Windows\CbsTemp\31255760_562088373\Windows10.0-KB5087545-x64.cab\Cab_1_for_KB5087545.cab
71240: 2026-05-26 07:26:47, Info                  CBS    Extracting all files from cabinet \\?\C:\Windows\CbsTemp\31255760_562088373\Windows10.0-KB5087545-x64.cab\Cab_2_for_KB5087545.cab
71261: 2026-05-26 07:27:31, Info                  CBS    Extracting all files from cabinet \\?\C:\Windows\CbsTemp\31255760_562088373\Windows10.0-KB5087545-x64.cab\Cab_3_for_KB5087545.cab
```

## 2. First attempt - specific CBS error

```text
1902167: 2026-05-26 07:33:59, Error                 CSI    0000161f (F) HRESULT_FROM_WIN32(ERROR_SXS_ASSEMBLY_MISSING) #12704388# from Windows::ServicingAPI::CCSITransaction::ICSITransaction_PinDeployment(Flags = 0, a = Microsoft-Windows-Editions-ServerStandard-Deployment-LanguagePack, version 10.0.20348.3328, arch amd64, culture [l:5]'pl-PL', nonSxS, pkt {l:8 b:31bf3856ad364e35}, cb = (null), s = (null), rid = 'Microsoft-Windows-Editions-ServerStandard-Package~31bf3856ad364e35~amd64~pl-PL~10.0.20348.3328.Microsoft-Windows-Editions-ServerStandard-Package', rah = ([gle=0x80073701]
1902168: 2026-05-26 07:33:59, Error                 CSI    null), manpath = (null), catpath = (null), ed = 0, disp = 0)[gle=0x80073701]
1902169: 2026-05-26 07:33:59, Info                  CBS    Failed to pin deployment while resolving Update: Microsoft-Windows-Editions-ServerStandard-Package~31bf3856ad364e35~amd64~pl-PL~10.0.20348.3328.Microsoft-Windows-Editions-ServerStandard-Package from file: (null) [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1902170: 2026-05-26 07:33:59, Info                  CBS    Failed to bulk stage deployment manifest and pin deployment for package:Microsoft-Windows-PowerShell-ISE-FOD-Package~31bf3856ad364e35~wow64~en-US~10.0.20348.1 [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1902175: 2026-05-26 07:33:59, Info                  CBS    Failed to resolve execution chain. [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1902176: 2026-05-26 07:33:59, Error                 CBS    Failed to process single phase execution. [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1902177: 2026-05-26 07:33:59, Info                  CBS    WER: Generating failure report for package: Package_for_RollupFix~31bf3856ad364e35~amd64~~20348.5139.1.14, status: 0x80073701, failure source: Resolve, start state: Absent, target state: Installed, client id: UpdateAgentLCU
1902184: 2026-05-26 07:34:00, Info                  CBS    Reporting package change completion for package: Package_for_RollupFix~31bf3856ad364e35~amd64~~20348.5139.1.14, current: Absent, original: Absent, target: Installed, status: 0x80073701, failure source: Resolve, failure details: "(null)", client id: UpdateAgentLCU, initiated offline: False, execution sequence: 281, first merged sequence: 281, pending decision: PendingAvoided_DelayQueueSideStepped, primitive execution context: Interactive 
1902194: 2026-05-26 07:34:03, Info                  CBS    Exec: Processing complete.  Session: 31255760_562088373, Package: Package_for_RollupFix~31bf3856ad364e35~amd64~~20348.5139.1.14, Identifier: KB5087545 [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1902195: 2026-05-26 07:34:03, Error                 CBS    Failed to perform operation.  [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1902196: 2026-05-26 07:34:03, Info                  CBS    Session: 31255760_562088373 finalized. Reboot required: no [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1902197: 2026-05-26 07:34:03, Info                  CBS    Failed finalizing session [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1902198: 2026-05-26 07:34:03, Info                  CBS    Failed to call Process on TiWorker session [HRESULT = 0x80073701]
1902160: 2026-05-26 07:33:59, Error                 CSI    0000161d@2026/5/26:05:33:59.238 (F) onecore\base\wcp\componentstore\csd_locking.cpp(95): Error STATUS_SXS_ASSEMBLY_MISSING originated in function CCSDirectTransaction::LockComponent expression: (null)
1902166: 2026-05-26 07:33:59, Error                 CSI    0000161e (F) STATUS_SXS_ASSEMBLY_MISSING #12704522# from CCSDirectTransaction::OperateEnding at index 0 of 1 operations, disposition 2[gle=0xd015000c]
```

## 3. Second KB5087545 installation attempt - launch

```text
2265: 2026-05-26 07:44:08, Info                  CBS    Exec: Processing started.  Client: UpdateAgentLCU, Session: 31255762_2704478870, Package: Package_for_RollupFix~31bf3856ad364e35~amd64~~20348.5139.1.14, Identifier: KB5087545
2293: 2026-05-26 07:44:08, Info                  CBS    Appl: Evaluating package applicability for package Package_for_RollupFix~31bf3856ad364e35~amd64~~20348.5139.1.14, applicable state: Installed
2294: 2026-05-26 07:44:08, Info                  CBS    Exec: Extracting package: Package_for_RollupFix~31bf3856ad364e35~amd64~~20348.5139.1.14
2130: 2026-05-26 07:43:50, Info                  CBS    ActionList: Adding package: \\?\C:\Windows\SoftwareDistribution\Download\03964adf9da69748b586449c281feaf9\Windows10.0-KB5087545-x64.cab
2296: 2026-05-26 07:44:08, Info                  CBS    Extracting all files from cabinet \\?\C:\Windows\SoftwareDistribution\Download\03964adf9da69748b586449c281feaf9\Windows10.0-KB5087545-x64.cab
2355: 2026-05-26 07:44:09, Info                  CBS    Extracting all files from cabinet \\?\C:\Windows\CbsTemp\31255762_2704478870\Windows10.0-KB5087545-x64.cab\Cab_1_for_KB5087545.cab
3338: 2026-05-26 07:44:54, Info                  CBS    Extracting all files from cabinet \\?\C:\Windows\CbsTemp\31255762_2704478870\Windows10.0-KB5087545-x64.cab\Cab_2_for_KB5087545.cab
3348: 2026-05-26 07:45:41, Info                  CBS    Extracting all files from cabinet \\?\C:\Windows\CbsTemp\31255762_2704478870\Windows10.0-KB5087545-x64.cab\Cab_3_for_KB5087545.cab
```

## 4. Second try - same CBS error

```text
1834033: 2026-05-26 07:50:12, Error                 CSI    00001663 (F) HRESULT_FROM_WIN32(ERROR_SXS_ASSEMBLY_MISSING) #14366062# from Windows::ServicingAPI::CCSITransaction::ICSITransaction_PinDeployment(Flags = 0, a = Microsoft-Windows-Editions-ServerStandard-Deployment-LanguagePack, version 10.0.20348.3328, arch amd64, culture [l:5]'pl-PL', nonSxS, pkt {l:8 b:31bf3856ad364e35}, cb = (null), s = (null), rid = 'Microsoft-Windows-Editions-ServerStandard-Package~31bf3856ad364e35~amd64~pl-PL~10.0.20348.3328.Microsoft-Windows-Editions-ServerStandard-Package', rah = ([gle=0x80073701]
1834034: 2026-05-26 07:50:12, Error                 CSI    null), manpath = (null), catpath = (null), ed = 0, disp = 0)[gle=0x80073701]
1834035: 2026-05-26 07:50:12, Info                  CBS    Failed to pin deployment while resolving Update: Microsoft-Windows-Editions-ServerStandard-Package~31bf3856ad364e35~amd64~pl-PL~10.0.20348.3328.Microsoft-Windows-Editions-ServerStandard-Package from file: (null) [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1834036: 2026-05-26 07:50:12, Info                  CBS    Failed to bulk stage deployment manifest and pin deployment for package:Microsoft-Windows-PowerShell-ISE-FOD-Package~31bf3856ad364e35~wow64~en-US~10.0.20348.1 [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1834161: 2026-05-26 07:50:12, Info                  CBS    Failed to resolve execution chain. [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1834162: 2026-05-26 07:50:12, Error                 CBS    Failed to process single phase execution. [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1834163: 2026-05-26 07:50:12, Info                  CBS    WER: Generating failure report for package: Package_for_RollupFix~31bf3856ad364e35~amd64~~20348.5139.1.14, status: 0x80073701, failure source: Resolve, start state: Absent, target state: Installed, client id: UpdateAgentLCU
1834292: 2026-05-26 07:50:13, Info                  CBS    Reporting package change completion for package: Package_for_RollupFix~31bf3856ad364e35~amd64~~20348.5139.1.14, current: Absent, original: Absent, target: Installed, status: 0x80073701, failure source: Resolve, failure details: "(null)", client id: UpdateAgentLCU, initiated offline: False, execution sequence: 284, first merged sequence: 284, pending decision: InteractiveInstallFailed, primitive execution context: Interactive 
1834300: 2026-05-26 07:50:14, Info                  CBS    Exec: Processing complete.  Session: 31255762_2704478870, Package: Package_for_RollupFix~31bf3856ad364e35~amd64~~20348.5139.1.14, Identifier: KB5087545 [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1834301: 2026-05-26 07:50:14, Error                 CBS    Failed to perform operation.  [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1834302: 2026-05-26 07:50:14, Info                  CBS    Session: 31255762_2704478870 finalized. Reboot required: no [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1834303: 2026-05-26 07:50:14, Info                  CBS    Failed finalizing session [HRESULT = 0x80073701 - ERROR_SXS_ASSEMBLY_MISSING]
1834304: 2026-05-26 07:50:14, Info                  CBS    Failed to call Process on TiWorker session [HRESULT = 0x80073701]
1834025: 2026-05-26 07:50:12, Error                 CSI    00001661@2026/5/26:05:50:12.433 (F) onecore\base\wcp\componentstore\csd_locking.cpp(95): Error STATUS_SXS_ASSEMBLY_MISSING originated in function CCSDirectTransaction::LockComponent expression: (null)
1834032: 2026-05-26 07:50:12, Error                 CSI    00001662 (F) STATUS_SXS_ASSEMBLY_MISSING #14366196# from CCSDirectTransaction::OperateEnding at index 0 of 1 operations, disposition 2[gle=0xd015000c]
```

## 5. Short technical conclusion

The two attempts run into the same error:

```text
0x80073701 - ERROR_SXS_ASSEMBLY_MISSING
Failed to pin deployment
Microsoft-Windows-Editions-ServerStandard-Deployment-LanguagePack
version 10.0.20348.3328
culture pl-PL
Package_for_RollupFix~31bf3856ad364e35~amd64~~20348.5139.1.14
Identifier: KB5087545
```

Based on this, the installation of KB5087545 does not fail due to a download error, but rather during the CBS resolve / deployment pinning phase on an old `pl-PL` ServerStandard language pack component chain.