After a lot of experiences, involving the cmdlets of PowerShell and good old STSADM, if you ever stumble onto an error like “Error occurred in deployment step ‘xxxxxxxxx’: A feature with ID 1x/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx has already been installed in this farm. Use the force attribute to explicitly re-install the feature” do this:
- Open the feature on design view
- Open the Properties tab next to Solution Explorer
- Set the Always Force Install property as TRUE
If you deploy the solution and the feature already exists it will be overwritten and the problem is solved. I don’t know if this is the best solution, but it’s one that worked just fine for me.