Exhibit 99.1

Guidance Software Reports

2017 Second Quarter Financial Results

PASADENA, Calif. – August 1, 2017 – Guidance Software, Inc. (NASDAQ: GUID) today reported financial results for the second quarter ended June 30, 2017.

Financial results for the second quarter of 2017, on a generally accepted accounting principles (GAAP) basis, include:

·                 Revenue of $24.7 million, compared to $27.6 million in the second quarter of 2016

·                 Net loss of $1.2 million, or ($0.04) per share, compared to a net loss of $9.7 million, or ($0.33) per share, in the second quarter of 2016

·                 EBITDA of ($31,000), compared to EBITDA of ($8.4) million in the second quarter of 2016

Financial results, on a non-GAAP basis, which excludes share-based compensation, amortization of intangibles, realignment expenses and income taxes, include:

·                 Non-GAAP net income of $1.6 million, or $0.05 per share, in the second quarter of 2017, compared to non-GAAP net loss of $2.4 million, or ($0.08) per share, in the second quarter of 2016

·                 Non-GAAP EBITDA of $2.4 million, compared to non-GAAP EBITDA of ($1.4) million in the second quarter of 2016

2017 Financial Outlook

The Company has suspended forward looking guidance pending the outcome of the previously announced acquisition of the Company by OpenText.

In light of the foregoing, the Company will not be hosting a conference call today.

About Guidance Software:

Guidance (NASDAQ: GUID) exists to turn chaos and the unknown into order and the known so that companies and their customers can go about their daily lives as usual without worry or disruption, knowing their most valuable information is safe and secure. The makers of EnCase®, the gold standard in forensic security, and EnForce™, an automated cyber risk management platform, Guidance provides a mission-critical foundation of market-leading applications that offer deep 360-degree visibility across all endpoints, devices and networks, allowing proactive identification and remediation of threats.

From retail to financial institutions, our field-tested and court-proven solutions are deployed on an estimated 33 million endpoints at more than 70 of the Fortune 100 and hundreds of agencies worldwide, from beginning to endpoint.

For more information about Guidance Software, please visit guidancesoftware.com, “Like” our Facebook page, follow us on Twitter, or follow our LinkedIn page.

Guidance Software®, EnCase® and EnForce™ are trademarks owned by Guidance Software and may not be used without prior written permission. All other trademarks and copyrights are the property of their respective owners.

Non-GAAP Financial Measures

Guidance Software reports its financial results in accordance with generally accepted accounting principles, or GAAP. To supplement this information, we present from time to time non-GAAP gross profit, operating expenses, operating income (loss) and net income (loss), as well as non-GAAP net income (loss) per share. Non-GAAP gross profit consists of GAAP gross profit as reported and adds back realignment expenses and share-based compensation expense booked for GAAP purposes. Non-GAAP operating income (loss) consists of GAAP operating income (loss) as reported and excludes realignment expenses, amortization of intangibles, litigation settlements, proxy contest expenses and share-based compensation expense. Non-GAAP net income (loss) consists of GAAP operating income (loss) as reported and excludes realignment expenses, amortization of intangibles, litigation settlements, proxy contest expense and share-based compensation expense and the income tax (benefit) provision.

We use these non-GAAP financial measures for internal managerial purposes, when publicly providing our business outlook, and to facilitate period-to-period comparisons. We describe additional information specific to each item excluded from our non-GAAP financial measures below. Management and the Board of Directors do not consider these excluded items for purposes of evaluating the performance of the Company, its business units and its management teams and when making decisions to allocate resources among the Company’s business units. Management generally compensates for limitations in the use of non-GAAP financial measures by relying on comparable GAAP financial measures and providing investors with a reconciliation of the non-GAAP financial measures only in addition to and in conjunction with results presented in accordance with GAAP.  We believe that these non-GAAP financial measures reflect an additional way of viewing aspects of our operations that, when viewed with our GAAP results, provide a more complete understanding of factors and trends affecting our business.  These non-GAAP measures should be considered as a supplement to, and not as a substitute for, or superior to, the comparable financial measures calculated in accordance with GAAP.

A reconciliation of our non-GAAP forward-looking measures to corresponding GAAP forward-looking measures is not available as a result of the uncertainty, and potential variability, in the forward looking estimates of the reconciling items between such non-GAAP forward-looking measures and the comparable forward-looking GAAP measures. Certain factors that are materially significant to our ability to estimate these items are out of our control and/or cannot be reasonably predicted, including the timing and amount of realignment expenses, amortization of intangibles, share-based compensation expense and income taxes.

Realignment Expenses. Realignment expenses represent severance and related employment costs associated with a reduction in headcount. Guidance Software excludes realignment expenses from non-GAAP gross profit, non-GAAP operating expenses, non-GAAP operating income (loss) and non-GAAP net income (loss) because it believes (i) the amount of such expenses in any specific period may not directly correlate to the underlying performance of Guidance Software business operations and (ii) such expenses are not expected to recur in future periods.

Proxy Contest Expenses. Proxy contest expenses represent one-time legal and other consulting expenses related to the proxy contest between Guidance Software and its founder and former chairman, which was settled on April 22, 2016. Guidance Software excludes proxy contest expenses from non-GAAP operating expenses, non-GAAP operating income (loss) and non-GAAP net income (loss) because it believes (i) the amount of such expenses in any specific period may not directly correlate to the underlying performance of Guidance Software business operations and (ii) such expenses are uncommon and not expected to recur in future periods.

Litigation Settlement. Litigation settlement expense represents a one-time settlement expense of a patent infringement lawsuit with MyKey Technology, LLC.  Guidance Software excludes litigation settlement expense from non-GAAP operating income and non-GAAP net income because it believes (i) the amount of such expense may not directly correlate to the underlying performance of Guidance Software business operations and

(ii) such expense is uncommon and not expected to recur in future periods.

Amortization of Intangibles. Amortization of intangibles is a non-cash expense arising from the acquisition of intangible assets in connection with acquisitions. Guidance Software excludes acquisition-related amortization expense from non-GAAP operating expenses, non-GAAP operating income (loss) and non-GAAP net income (loss) because it believes (i) the amount of such expenses in any specific period may not directly correlate to the underlying performance of Guidance Software business operations and (ii) such expenses can vary significantly between periods as a result of new acquisitions and full amortization of previously acquired intangible assets. Investors should note that the use of these intangible assets contributed to revenue in the periods presented and will contribute to future revenue generation and the related amortization expense will recur in future periods.

Share-based Compensation Expense. Share-based compensation expense is a non-cash expense arising from the grant of stock awards to employees. Guidance Software excludes share-based compensation expense from non-GAAP gross profit, non-GAAP operating expenses, non-GAAP operating income (loss) and non-GAAP net income (loss) because it believes (i) the amount of such expenses in any specific period may not directly correlate to the underlying performance of Guidance Software business operations and (ii) such expenses can vary significantly between periods as a result of the timing of grants of new share-based awards. Investors should note that share-based compensation is a key incentive offered to employees whose efforts contributed to the operating results in the periods presented and are expected to contribute to operating results in future periods and such expense will recur in future periods.

INVESTOR CONTACT

Rasmus van der Colff

Guidance Software, Inc.

626-768-4607

investorrelations@guidancesoftware.com

GUID-F

Guidance Software, Inc.

Unaudited Condensed Consolidated Statements of Operations

(in thousands, except per share amounts)

Guidance Software, Inc.

Calculation of Pre-Tax Non-GAAP Income

(unaudited)

(in thousands, except per share amounts)

Guidance Software, Inc

Reconciliation of GAAP to Non-GAAP Financial Measures

(Unaudited and in thousands, except per share amounts)

Guidance Software, Inc.

Unaudited Condensed Consolidated Balance Sheets

(in thousands)

Guidance Software, Inc

Unaudited Cash Flow Summary

(in thousands)