When installing the SharePoint 2013 Preview Prerequisites you may get the error message "Appfabric installation failed because installer MSI returned with error code:1603". In my case it happened because I had uninstalled Appfabric and tried to install it again.
In order to eliminate this error, the Powershell path must be mapped to the Environment Variable PsModulesPath.
Add the following path:
Then you may proceed with the installation of the SharePoint 2013 Preview Prerequisites.
I hope it helps.
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