Since this is the first Google result for "appium cannot enter package empty drop down" I am necro-posting my Windows7 workaround. It astounds me that an issue spanning so many years has not been definitively fixed...
Thus, as a workaround for accessing apps already installed on the device, Shut down Appium and then edit the user.config file in:
Therein you will find the following XML markup among all other (supposedly) UI configurable settings:
<setting name="AndroidPackage" serializeAs="String">
<setting name="AndroidActivity" serializeAs="String">
Change the values, save, then relaunch Appium.
The UI will still be broken, but the server will start correctly with user.config properties.
For good measure, you may wish to delete any files from past Appium version folders.
It should be noted that I install my Appium server in a non-standard location (i.e. NOT in C:\Program Files (x86)\Appium) as I prefer to separate my Dev environment from my OS environment.
Hope this helps.