We are experiencing an issue that is impacting canvas apps which were saved in a recent prior version and then opened in the latest studio version. This issue only affects the preview region which requires opt in. We are rolling out a fix to resolve the issue.
[3/19/2019] Customers using PowerApps for Windows may experience failures downloading apps. The typical symptom is an error dialog stating "This app didn't install correctly." We are urgently investigating the issue and preparing a fix.