Are you facing Macbook Pro prohibitory sign on startup? It is a very critical issue for Macbook Pro users. Generally this type of problem occurs due to any major corruption issue. There are various reasons which can cause corruption in Macbook Pro such as virus attack, deleted or missing system, corruption in header node, damaged B-tree structure, improper installation of OS. In such situation whenever users try to boot their Macbook system Macbook Pro prohibitory sign on startup, appears and on the screen and interrupt thew process in the middle. It can also be very risky for the data stored to your laptop thus it is very important to resolve this problem as soon as possible. Formatting is the only possible way to fix Macbook Pro prohibitory sign on startup issue. It will troubleshoot the corruption permanently and fix this issue. However meanwhile all the files stored in Macbook hard drive will also get removed by formatting but don't take tension you can get back all your precious files easily. once Macbook Pro prohibitory sign on startup issue get rectified then you can easily restore all your precious files with the help of Mac Data Recovery Software.