regex101: Maintain portion in the middle

Group 1(\[\[outlook:)

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

outlook:the literal text outlook: (case sensitive)

Group 2([0-9A-Z]*)

Character Class[0-9A-Z]*

*matches any number of characters from the set below:

0-9one character from 0 (48₁₀) to 9 (57₁₀)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

Group 3(\]\[)

\]the literal ] (93₁₀ / 135₈ / 5D₁₆)

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

Group 4(.*)

.*any character (except for line terminators), repeated any number of times

Group 5(\]\])

\]the literal ] (93₁₀ / 135₈ / 5D₁₆)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

Search reference

Regular Expression

(\[\[outlook:)([0-9A-Z]*)(\]\[)(.*)(\]\])

New

[[outlook:000000003730C053465F314590D066368CF3097B0700AAF83E03F96EDC42918E044642DEDDB3000013E2000E0000AAF83E03F96EDC42918E044642DEDDB3000013E2EFD30000][MESSAGE: RE: Subject of the Message (Sendername Senderfirstname) 2014-08-05 19:48]]

[[http:000000003730C053465F314590D066368CF3097B0700AAF83E03F96EDC42918E044642DEDDB3000013E2000E0000AAF83E03F96EDC42918E044642DEDDB3000013E2EFD30000][MESSAGE: RE: Subject of the Message (Sendername Senderfirstname) 2014-08-05 19:48]]

Substitution

[[path\\outlook\\\2\.msg\3\4\5