OK. The /e option doesn't give a lot of information. Can you try to debug if the error stems from any of the ComRegisterFunction() inside the failed assembly? You can do so by setting esriRegasm.exe as the debugging external program in Visual Studio. (And it is better if you remove or comment out the BeforeClean/AfterBuild xml from the project file before debugging.)
Under Start Action
------------------
Start external program:
C:\Program Files\Common Files\ArcGIS\bin\ESRIRegAsm.exe
or on a 64 bit OS
C:\Program Files (x86)\Common Files\ArcGIS\bin\ESRIRegAsm.exe
Under Start Options
-------------------
Command line arguments:
"NewFindAcctTool.dll" /p:Desktop /e
Working directory:
{directory of the NewFindAcctTool.dll}
<Target Name="BeforeClean"> <Exec WorkingDirectory="$(CommonProgramFiles)\ArcGIS\bin" Command="esriRegasm.exe "$(TargetPath)" /p:Desktop /u /s" Condition="Exists('$(TargetPath)')"/> </Target> <Target Name="AfterBuild"> <Exec WorkingDirectory="$(CommonProgramFiles)\ArcGIS\bin" Command="esriRegasm.exe "$(TargetPath)" /p:Desktop /s"/> </Target>
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ESRIRegAsm::Register
Command line: "NewFindAcctTool.dll" /p:Desktop /e
Registry Capture On.
Registering managed library...
Managed Exception: Could not load file or assembly 'file:///I:\FELLJ\FellJGIS\
Projects\Development\dotNETProjects\NewFindTool\NewFindAcctTool\NewFindAcctTool\
bin\Debug\newfindaccttool.dll' or one of its dependencies. Operation is not supp
orted. (Exception from HRESULT: 0x80131515)
Registry Capture Off.
Operation Failed
003B6388
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Press Enter to continue...