On the gpg4o support page you will find all the information you need to use gpg4o successfully.

Encrypt emails in a simple, user-friendly and yet secure way – seamlessly integrated into the Microsoft Outlook user interface with gpg4o.

Download Center


Download the ADMX templates for setting up the group policies for gpg4o here.


Whether standard processes, module functions or questions about operation: In the manual you will find all the important information about gpg4o.

Release Notes

The latest features, enhancements and further developments in one document – get an overview of all the changes in the latest version.

Frequently Asked Questions

gpg4o is an add-in for Microsoft Outlook 2010/2013/2016® that can be used to encrypt, decrypt, sign and verify messages and their attachments. gpg4o uses GnuPG, a free encryption software.

gpg4o uses an asymmetric encryption method and follows the OpenPGP standard. This system uses key pairs consisting of a private and a public key. The private key is kept secret, the public key is passed on to your contacts. As soon as the public key of the other communication person has been received, it can be used to encrypt an e-mail message to the recipients concerned. This message can then only be decrypted again with the recipient’s private key. You can find out how to send and receive encrypted and signed files in the manual.

gpg4o requires Microsoft Outlook 2010®, Microsoft Outlook 2013® or Microsoft Outlook 2016® and an installed version of GnuPG v1.4.21 or higher. As of version 3.2, the installation of GnuPG is integrated into the setup of gpg4o. The necessary installation files can be found in the download area of gpg4o. The steps required for installation are described in the manual. Windows 7® (32/64 bit), Windows 8® (32/64 bit) or Windows 10® (32/64 bit) can be used as the operating system. For detailed information, please refer to the System requirements page.

If the trial period is not long enough, we can extend it for you. Contact us at [email protected]. You can still read your messages encrypted with gpg4o as long as you do not uninstall gpg4o. As soon as you have purchased a license for gpg4o and imported it, gpg4o can be fully used again within the scope of the purchased license without further installation.

When importing a license file, “No license file” is displayed or a license file, as an attachment to an e-mail, cannot be imported. If you encounter these errors, we recommend that you check whether you have installed GnuPG correctly and entered the path to gpg.exe/gpg2.exe correctly in the settings. If necessary, reinstall GnuPG on your computer.

If you have deleted the account with the licensed e-mail address in Outlook, gpg4o will no longer recognize your current license as the associated e-mail account has been deleted and will go into test version mode. You must now create and import a new license with your new e-mail address in the license management. You will then have a fully functional gpg4o again.

I receive the license from the license management by e-mail and cannot import it. The following error message appears: “Your license does not match the current Outlook account. Please adjust your license in the gpg4o license management or contact the sales department.” Check whether the e-mail address in your Outlook is identical to the e-mail address in the license. The two e-mail addresses must be the same. If this is not the case, correct the e-mail address of your license via the gpg4o license management.

The license of gpg4o entitles you to use gpg4o with the licensed email address and other email addresses within the same installation for an unlimited period of time. During the product maintenance period, you have the option of contacting support if you have any questions or problems and obtaining and installing updates. Each license of gpg4o may be used simultaneously on several computers and in different profiles (e.g. desktop PC + laptop) as long as the licensed e-mail address is set up in Outlook on both computers. The term of the product maintenance and the possibility of using the license begin with the first download of the purchased license. If you intend to use gpg4o with different profiles within the same Outlook installation, please contact us.

If the product maintenance/support has expired, gpg4o can still be used. This means that you can continue to send encrypted/signed emails and read encrypted/signed emails. However, you will not receive any further updates from gpg4o.

By purchasing an extension of the product maintenance/support, you can continue to receive new updates for gpg4o. The gpg4o development team is constantly improving the program and integrating suggestions from customers into a new version. After purchasing an extended license, it must be imported into gpg4o once.

When updating gpg4o, only the program files are updated. Your GnuPG keyring and your gpg4o settings will be adopted.

Yes, importing and exporting keys is also possible via drag ‘n drop.

Yes, gpg4o supports encrypted emails in HTML format.

gpg4o uses the PGP/Inline method for sending encrypted e-mails. The PGP/MIME format is supported for reading.

If you send an e-mail and activate the options for “Encrypt” and/or “Sign”, these settings apply to both the text of the e-mail and its attachments. Only the subject line and the recipient list remain unencrypted. If desired, gpg4o encrypts only the attachment of a message.

Create a backup on your old computer with gpg4o. You can import this backup on the new computer after successful installation of gpg4o and GnuPG. Only save the backup on your own physical data carriers. The backup contains your personal data, so you should never upload the backup to the cloud.

If your computer is defective, you will no longer have access to your hard disks. You can no longer access the private keys, so you cannot decrypt old e-mails encrypted with these keys. To protect yourself from this, please create a backup. Only save the backup on your own physical data carriers. The backup contains your personal data, so you should never upload the backup to the cloud.

Do you have any questions about discounts for different customer groups (retailers, pupils and students, educational institutions or non-profit organizations)? Do you have any questions about the graduated prices of the individual products? If you have any problems or questions regarding the purchase of gpg4o, please use the contact form or send an e-mail to [email protected]

If you have any problems or questions when installing or using gpg4o, please follow the instructions on the support page. If an error has occurred, please remember to attach the automatically generated log file. You can help us if you describe any errors you observe as precisely as possible and indicate what steps you took before the error occurred.

So that our development department can eliminate any errors that may occur as efficiently as possible, status messages from gpg4o are written in so-called log files. These status messages do not contain any personal information, passwords or contents of emails. Before sending the e-mail with the log files, you can view the transmitted information by unpacking the attached .zip file. All files contained therein consist of plain text.

The option “Hide attachment names” is activated by default in gpg4o and increases the confidentiality of your emails by hiding the file name. If a recipient cannot process these file names, you can deactivate this option in the gpg4o settings. In gpg4o in the “Settings”/”Send/Receive Settings”/”Send Attachment Send Options” you can activate the option “Keep attachment names”, which increases compatibility with other OpenPGP implementations.