Can't access your data? DO NOT RUN CHKDSK!!!
We see this happen a lot. Unfortunately Windows is not very honest when it comes to information about chkdsk and what it does exactly. All chkdsk wants is a consistent file system and it will do anything to achieve this, including deleting your precious data. To put it simple: Chkdsk repairs the file system, not the data. So when faced with disk problems or data you can't access, never run chkdsk. Recovering data becomes much more difficult after chkdsk has run, keep this is mind. Instead use a tool like iRecover. Read more here.