I found a bug which clear the content of my mxd, but I am unable to report this, since the reporting system has changed, I wonder if someone else also had the similar problem and found out the reason.
The issue was that: I have organized an mxd with some spatial and non spatial data, i had different data frames in this mxd, after I was done saved my mxd file but when I re-open it again I found out that the content was removed. The size of the mxd was same but I was unable to visualize the content. There was some external data connection with SQL-server, that connections were still in mxd but not the content from gdb.
Had anyone encountered with this error before ?