Error: "The Workstation service depends on the bowser service which failed to start because of the following error: Windows cannot verify the digital signature for this file." when you try to start Workstation service on SBS 2008

To resolve this issue, follow the below steps:

Method 1:

1.) Launch Command Prompt with elevated privileges.

2.) Run SFC /Scannow

Note: If the hash of the file \SystemRoot\WinSxS\amd64_microsoft-windows-bowser_31bf3856ad364e35_6.0.6002.18407_none_846ba9afd9bdf564\bowser.sys does not match the actual file, this method will fail. On analyzing C:\Windows\Logs\CBS\CBS.log, you will find something similar:

2011-06-17 13:19:55, Info CSI 00000293 Hashes for file member \SystemRoot\WinSxS\amd64_microsoft-windows-bowser_31bf3856ad364e35_6.0.6002.18407_none_846ba9afd9bdf564\bowser.sys do not match actual file [l:20{10}]"bowser.sys" :
  Found: {l:32 b:i/z5NL6xksMrSoIOxl0S+UkIy1o2yi247TqBPlZexiE=} Expected: {l:32 b:UPkkK3EEYH5jOrr04KITwcEia/gff7TiFqnoeCR7how=}
2011-06-17 13:19:55, Info                  CSI    00000294 [SR] Cannot repair member file [l:20{10}]"bowser.sys" of Microsoft-Windows-Bowser, Version = 6.0.6002.18407, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2011-06-17 13:19:55, Info                  CSI    00000295 Hashes for file member \SystemRoot\WinSxS\amd64_microsoft-windows-bowser_31bf3856ad364e35_6.0.6002.18407_none_846ba9afd9bdf564\bowser.sys do not match actual file [l:20{10}]"bowser.sys" :
  Found: {l:32 b:i/z5NL6xksMrSoIOxl0S+UkIy1o2yi247TqBPlZexiE=} Expected: {l:32 b:UPkkK3EEYH5jOrr04KITwcEia/gff7TiFqnoeCR7how=}
2011-06-17 13:19:55, Info                  CSI    00000296 [SR] Cannot repair member file [l:20{10}]"bowser.sys" of Microsoft-Windows-Bowser, Version = 6.0.6002.18407, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2011-06-17 13:19:55, Info                  CSI    00000297 [SR] This component was referenced by [l:156{78}]"Package_7_for_KB2511455~31bf3856ad364e35~amd64~~6.0.1.0.2511455-48_neutral_GDR"
2011-06-17 13:19:55, Info                  CSI    00000298 Hashes for file member \??\C:\Windows\System32\drivers\bowser.sys do not match actual file [l:20{10}]"bowser.sys" :
  Found: {l:32 b:i/z5NL6xksMrSoIOxl0S+UkIy1o2yi247TqBPlZexiE=} Expected: {l:32 b:UPkkK3EEYH5jOrr04KITwcEia/gff7TiFqnoeCR7how=}
2011-06-17 13:19:55, Info                  CSI    00000299 Hashes for file member \SystemRoot\WinSxS\amd64_microsoft-windows-bowser_31bf3856ad364e35_6.0.6002.18407_none_846ba9afd9bdf564\bowser.sys do not match actual file [l:20{10}]"bowser.sys" :
  Found: {l:32 b:i/z5NL6xksMrSoIOxl0S+UkIy1o2yi247TqBPlZexiE=} Expected: {l:32 b:UPkkK3EEYH5jOrr04KITwcEia/gff7TiFqnoeCR7how=}
2011-06-17 13:19:55, Info CSI 0000029a [SR] Could not reproject corrupted file [ml:520{260},l:62{31}]"\??\C:\Windows\System32\drivers"\[l:20{10}]"bowser.sys"; source file in store is also corrupted


If this is the case, you need to proceed to method 2.

Method 2:

Replace the bowser.sys file on the problematic server from a good working server. You need to replace the file in the following locations:

C:\Windows\System32\Drivers\

C:\Windows\WinSxS\amd64_microsoft-windows-bowser_31bf3856ad364e35_6.0.6002.18407_none_846ba9afd9bdf564\