Problems installing EPiServer Commerce

Are you having troubles installing Commerce? 

Are you receiving this error message:

System.Management.Automation.PSInvalidOperationException: The WriteObject and WriteError methods cannot be called from outside the overrides of the BeginProcessing, ProcessRecord, and EndProcessing methods, and only from that same thread. Validate that the cmdlet makes these calls correctly, or please contact Microsoft Support Services.

Unfortunately the installation should copy the log files to the application root, but it doesn't seems to do that. To see the actual error and not just a generic Powershell error, we need to modify the installation script a bit (find this in the Commerce installation directory).

First comment out the line that deletes the temp folder:

# DeleteFolder $unzipTempFolder

Then remove the signature at the bottom of the file as it's invalid now and then save the file.

# SIG # Begin signature block
# MIIVNwYJKoZIhvcNAQcCoIIVKDCCFSQCAQExCzAJBgUrDgMCGgUAMGkGCisGAQQB
# gjcCAQSgWzBZMDQGCisGAQQBgjcCAR4wJgIDAQAABBAfzDtgWUsITrck0sYpfvNR
..... lots of text....
# ISmDxA7ThKuIxlg=
# SIG # End signature block

As the file is no longer signed, we can't run it before we have made some PowerShell policy adjustments. The default policy is to not allow unsigned scripts to run. So we must change it

PS C:\Users\tobias> Set-ExecutionPolicy 'unrestricted'

Now run EPiServer deployment center and run the Commerce installation and after it have failed you should have a new catalog in your c: drive. In that folder you should find a log folder which contains the installation logs (installer logs). There you will find what the error really was.

Hope this helps with your Commerce install issues!