SYMPTOM:
Users running a report in Web might see the following error message:

“ReferenceError: mstrLocalStorage is not defined”
CAUSE:
The error message points that mstrLocalStorage.js cannot be located. A possible cause is that some files in the Virtual Directory were mistakenly edited or deleted.
ACTION:
A solution to this issue is either a repair installation or manual restoration of an out-of-the-box Virtual Directory. KB440402