Phone erases text messages and call log

This happens because of large applications are installed on the BlackBerry smartphone.
To resolve this issue, complete the following steps:-

1. Make sure that the BlackBerry Device Software is installed on the computer to display the correct total application space.
2. Determine the application space that is available on the BlackBerry smartphone by completing the following steps.

a) Connect the BlackBerry smartphone to the computer.
b) Open the BlackBerry Desktop Manager.
c) Double-click Application Loader.
d) At the Device Application Selection screen, under the application selection window, note the total application space.

NOTE:-Select the List additional applications that are installed on the connected device check box to include the applications that are installed outside of the BlackBerry Device Software applications and the file sizes.
3) Remove applications that are not required. For example, remove additional language packs and themes.