Unity3D 5 packages conflict

Question

I have Unity 5.0.2f1. Firstly, I've successfully added GooglePlayGamesPlugin-0.9.20.unitypackage to my project. Then, I've tried to import GoogleMobileAds.unitypackage, but I got these errors:

Error importing folder (The pathName assets/plugins is already mapped to fce8a713f1e5a4cc4b9973d1ef630f31. But the meta data wants it to be mapped to cbde64d36fd994c458fffca9e931b232)
Error importing folder (The pathName assets/plugins/android is already mapped to b8f0d9a6a7f9240c981894807effddbc. But the meta data wants it to be mapped to 2f5d736f7c4cb4c1e80d0816d0e81625)
Error importing folder (The pathName assets/plugins/ios is already mapped to 6490bb8acab6f4f92b29615e7429b8df. But the meta data wants it to be mapped to da135550add3c4abca622bda5280d204)

How to resolve this?

Answer 1

First make a backup of your project and delete your metadata files in your asset project folder and childs. Files with extension .meta

Answer 2

The easiest workaround I could come up with: 1. Within the Unity Editor, create a subfolder of the Assets folder, for instance called TEMP123. 2. Move the entire (other) content of the Assets folder to TEMP123. 3. Import your package. 4. Manually merge the content of TEMP123back to the Assets folder.

Answer 3

If you see these kinds of errors, reimport all the assets. This reprocesses the metadata and the error goes off.