Sitecore Instance Manager - packages does not contain Web.config file

When attempting to import a Sitecore solution using Sitecore Instance Manager (SIM), the following error would display:

Wrong package for import. The package does not contain the Website/Web.config file.

Sitecore Instance Manager - missing Web.config file

Looking inside the package, there was a Web.config file inside a Website directory. The version of SIM was the latest at the time (1.5.0.2), and according to the SIM bug tracking this issue was resolved several (minor) releases ago.

It turns out that the Solution that I was trying to import, was generated months ago on a now outdated version of SIM. By re-exporting the solution using the latest version it could then be imported successfully.

If your solution uses Sitecore Experience Accelerator (SXA), you may need to download the QA version of SIM.