X0306 4 2021-10-06 0 0001644675 Mimecast Ltd MIME 0001676306 Murray Neil C/O MIMECAST NORTH AMERICA, INC. 191 SPRING STREET LEXINGTON MA 02421 1 0 0 0 Restricted Share Units 2021-10-06 4 A 0 2742 0.00 A 2742 D Ordinary Shares 769315 D Each restricted share unit represents a contingent right to receive one share of the Issuer's Ordinary Shares. These restricted share units were granted on October 6, 2021 and vest in full on the one year anniversary of the date of grant, provided that the Reporting Person remains a director of the Issuer on such vesting date. Exhibit 24 Power of Attorney (incorporated by reference to Power of Attorney filed as Exhibit 24 to Form 3 filed by the Reporting Person on April 2, 2018). /s/ Robert P. Nault, Attorney-in-Fact 2021-10-08