The language-neutral solution package was not found

This error pops up from time to time when trying to deploy a solution to SharePoint 2007 or 2010 and when it happens it doesn't easily go away:

Error occurred in deployment step 'Retract Solution': The language-neutral solution package was not found.

There are several things you can try to resolve the issue, in this specific order:

1. Close Visual Studio Solution and completely exit out of it, then run it again and compile. This sometimes fixes the issue. 
2. Right-Click on your Visual Studio Solution, select "Clean" Solution, then Right Click on SharePoint Project and choose "Retract". Rebuild and Deploy. 
3. In PowerShell running as Administrator run Uninstall-SPSolution: 
• Unistall-SPSolution -identity {Name of WSP File} -allwebapplications
4. In PowerShell running as Administrator run Remove-SPSolution:
• Remove-SPSolution -identity {Name of WSP File} -force
5. In PowerShell running as Administrator run the Delete() command:
• (Get-SPSolution {Name of WSP File}).Delete()

If items 1 through 4 doesn't fix it, item 5 will definitely do the trick, but it shouldn't be run unless all the other solutions fail. 

Pete Soheil

DigiOz Multimedia, Inc.

www.digioz.com