GUID Guidance Software, Inc.

EXPLANATORY NOTE

Deregistration of Securities

These Post-Effective Amendments relate to the following Registration Statements on Form S-8 (collectively, the “Registration Statements”) of Guidance Software, Inc. (the “Company”):

File No. 333-217641, pertaining to the registration of 2,000,000 shares of common stock, $.001 par value per share of the Company (“Common Stock”) issuable under the Guidance Software, Inc. 2017 Incentive Award Plan.

File No. 333-207209, pertaining to the registration of 3,000,000 shares of Common Stock, $.001 par value per share of the Company issuable under the Guidance Software, Inc. Second Amended and Restated 2004 Equity Incentive Plan.

File No. 333-184322, pertaining to the registration of 2,500,000 shares of Common Stock, $.001 par value per share of the Company issuable under the Guidance Software, Inc. Second Amended and Restated 2004 Equity Incentive Plan.

File No. 333-167656, pertaining to the registration of 2,086,439 shares of common stock, $.001 par value per share of the Company issuable under the Guidance Software, Inc. Second Amended and Restated 2004 Equity Incentive Plan.

File No. 333-140007, pertaining to the registration of 3,211,658 shares of common stock, $.001 par value per share, and 3,790,216 outstanding options to purchase shares of common stock, $0.001 par value per share, of the Company issuable under the Guidance Software, Inc. First Amended and Restated 2004 Equity Incentive Plan.

On July 25, 2017, the Company, Open Text Corporation, a corporation incorporated under the federal laws of Canada (“OpenText”), and Galileo Acquisition Sub Inc., a Delaware corporation and a wholly-owned subsidiary of OpenText (“Purchaser”), entered into an Agreement and Plan of Merger (the “Agreement”). The Agreement contemplated that Purchaser would be merged with and into the Company (the “Merger”) and that the Company would survive the Merger as a wholly-owned subsidiary of OpenText. The Merger became effective on September 14, 2017 (the “Effective Date”) as a result of filing a Certificate of Merger with the Secretary of State of the State of Delaware.

At the Effective Date, each share of common stock of the Company issued and outstanding immediately prior to the Merger (other than each share (i) owned by OpenText or the Company or held by a wholly-owned subsidiary of OpenText (including Purchaser) or the Company, which will be cancelled and cease to exist without any payment being made with respect to such share or (ii) owned by the Company’s stockholders who are entitled to and who properly exercised appraisal rights under Section 262 of the Delaware General Corporation Law with respect to such share) was converted into the right to receive $7.10 in cash, without interest, and net of applicable withholding of taxes.

As a result of the Merger, the Company has terminated all offerings of its securities pursuant to its existing registration statements, including the Registration Statements. In accordance with an undertaking made by the Company in the Registration Statements to remove from registration by means of a post–effective amendment any securities registered under the Registration Statements which remain unsold at the termination of the offering, the Company hereby removes from registration any securities registered under the Registration Statements which remained unsold as of the Effective Date.