You can reset your Master password but recovering the Master Password is not possible. The whole point of RoboForm security is that only the person who knows the Master Password can use RoboForm Data protected by this password.
If you forgot your Master Password (or if you do not remember creating one but RoboForm requests it from time to time) then the only course of action is to remove all RoboForm User Data files protected by the Master Password.
Select the RoboForm icon >>Options >> Security. Select "Change Master Password" button, click Next when asked to enter the password and then check "I do not remember a password for this data" checkbox when you are asked to enter the password to open a RoboForm file you do not know the password for (check "Do not ask next time" if you do not remember anything), click Next and follow the instructions to remove or set a new Master Password.