I got an email saying that storage check has now ended beta and people should now use "Storage sense" instead. Read below
Storage Check beta trial concluded. Hello, Storage Sense!
Hi,
With the inclusion of Storage Sense in Windows Phone 8.1 we no longer need to maintain a Lumia-specific Storage Check. Storage Sense does pretty much the same things...and more.
With Storage Sense you can check your storage space (both phone and SD card) and free up space by moving apps and games to your SD card (if you have one), uninstall apps, or delete downloaded files. Read the full details at windowsphone.com.
The new Storage Sense and other features of Windows Phone 8.1 will be available for all Windows Phone 8 Lumia devices through the Lumia Cyan software update, which has started rolling out. Check availability here:
http://www.nokia.com/global/support/software-update/wp8-software-update/
We hope that Lumia Storage Check has been serving you well and we wish to thank those that have been using the beta and providing feedback. Your help was essential in ironing out the bug that was preventing the app from working for some people, and you provided good input on using Maps on the SD card.
Please note that the current beta version of Storage Check will not report correct numbers for apps and is thus incompatible with the Windows Phone 8.1 release. However, as Maps data will be stored on phone memory by default, we will keep the old beta version of Storage Check available just for that purpose, so that you can change back to using phone memory without doing a 'reset my phone'.
We will now conclude the Lumia Storage Check beta trial at Nokia Beta Labs and the feedback forum will be archived.
- The Storage Check team