Today I updated to the preview version of Windows 10 and encountered several problems.
Since I got an error the first time which was related to SD card storage, I changed settings that apps are not stored on SD card but on local storage (internal memory).
Than I installed Windows 10 without any problems.
However, I have the following issues: - All live tiles are disappeared - All installed apps from the SD card are not shown in the app list - However, if I search for an application that is previously installed on SD card, the phone redirects me to the Store, where it is shown as already installed. I can start it up, but not install (reinstall) it.
I don't mind to reinstall all apps (although it were like 100-150 in total), but I mind about not being able to install apps anymore, which is the current situation.
Hope someone can help me.
Update: I could revert back to 8.1 thanks to a Microsoft Application. It took some time before all my applications were reinstalled, but in the end I only had to fill in all my passwords and authentication information in all applications which took me about 2 to 3 hours.
For me Windows 10 is unusable (even when released), because it does not support storing applications on SD card. Maybe Windows 10.1 (or 11). I hope it will not be a mandatory update/install process when Windows 10 is released officially.