:user1:example1@hotmail.com:4082e6739d188208d2450d1e03696b40:OdoA>D9e9VIOnP8^}M[e*FA)3!:Frankosh:test_93@hotmail.com:1bf4e6d1462b89977cf774c3dc1c666f:|Lt&A/+?%My._Ft+Tw1B7(?'[Sw/F5
:user2˜…:2example@hotmail.com:ac9ae85d0ad2f6328507bac7357dfdf4:(;J`#PQVde}),G*WoV%y&7:]:calefonaso:test@hotmail.com:08598769c7ee559e792be4d04e931140:7TJL|O}c:2YhJq?0[?4coLT~XjW"xm
:Ruziitto:example3@hotmail.com:fe71d6e50e0bb767a19e176c0d26eaed:rOSMJ|?~Y*jAp1#P,p)h)t:s:killer87:tested@gmail.com:4316edd511ea5d8b2a67748ded316497:z(=3;m#y0:+$WSjY6u@!WFyt{Ia

:user1:example1@hotmail.com:4082e6739d188208d2450d1e03696b40:OdoA>D9e9VIOnP8^}M[e*FA)3!
:Frankosh:test_93@hotmail.com:1bf4e6d1462b89977cf774c3dc1c666f:|Lt&A/+?%My._Ft+Tw1B7(?'[Sw/F5
:user2˜…:2example@hotmail.com:ac9ae85d0ad2f6328507bac7357dfdf4:(;J`#PQVde}),G*WoV%y&7:]
:calefonaso:test@hotmail.com:08598769c7ee559e792be4d04e931140:7TJL|O}c:2YhJq?0[?4coLT~XjW"xm
:Ruziitto:example3@hotmail.com:fe71d6e50e0bb767a19e176c0d26eaed:rOSMJ|?~Y*jAp1#P,p)h)t:s
:killer87:tested@gmail.com:4316edd511ea5d8b2a67748ded316497:z(=3;m#y0:+$WSjY6u@!WFyt{Ia

^           : begining of line
  (         : start group 1
    (?:     : start non capture group
      :     : a colon
      [^:]+ : 1 or more any character that is not a colon
    ){4}    : end group, must appear 4 times
  )         : end group 1
  :         : a colon  (To be sure to not add superfluous line break)

$1      : The content of group 1 (the first fourth columns in a line)
n      : a line break, you could use rn for windows
:       : colon, at the beginig of new lines

:user1:example1@hotmail.com:4082e6739d188208d2450d1e03696b40:OdoA>D9e9VIOnP8^}M[e*FA)3!
:Frankosh:test_93@hotmail.com:1bf4e6d1462b89977cf774c3dc1c666f:|Lt&A/+?%My._Ft+Tw1B7(?'[Sw/F5
:user2˜…:2example@hotmail.com:ac9ae85d0ad2f6328507bac7357dfdf4:(;J`#PQVde}),G*WoV%y&7
:]:calefonaso:test@hotmail.com:08598769c7ee559e792be4d04e931140:7TJL|O}c:2YhJq?0[?4coLT~XjW"xm
:Ruziitto:example3@hotmail.com:fe71d6e50e0bb767a19e176c0d26eaed:rOSMJ|?~Y*jAp1#P,p)h)t
:s:killer87:tested@gmail.com:4316edd511ea5d8b2a67748ded316497:z(=3;m#y0:+$WSjY6u@!WFyt{Ia