Can't enter license, OK button disabled, key not accepted

A license key can be rejected by the software for one of the following reasons:

Misspelled user name and/or license key

To avoid misspellings, we recommend that you copy both the user name and license key from the license certificate e-mail rather than enter them manually in the software. You can do so by using the Ctrl+C/Ctrl+V shortcuts on Windows/Linux and Cmd+C/Cmd+V shortcuts on Mac.

You should be looking for this section inside the license certificate e-mail:

=========INSTALLATION==========

Run <PRODUCT NAME> and follow the Installation Wizard's instructions. To register for use of the software or change your existing registration details, go to Help/Register menu of the software and enter the included below the User Name and License Key(s) into the registration dialog:

User Name: COPY/PASTE THIS NAME
License Key: COPY/PASTE THIS KEY

Some products use 4-line keys in the following format:

===== LICENSE BEGIN =====
NNNNNN-NNNNNNNN
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
===== LICENSE END =====

You need to copy the entire key on 4 distinct lines. Some mail clients may remove the line breaks between these lines rendering the key invalid when pasted.

Offline activation key from JetBrains account is a single long line of characters. You can drag&drop .txt file downloaded from your account into the key text field.

• Copy from the original e-mail view not modified by the mail client or other software (don't copy from a saved PDF).
• LICENSE BEGIN/LICENSE END lines are optional and can be omitted when copying.
• IntelliJ IDEA versions before 11.1.5 have a single line input field and will not work with 4-line license keys.
• Key groups are separated with the minus symbol (-), some clients can automatically replace it with a dash making the key not valid.
• OK button in the dialog will remain disabled until both the correct user name and the license key for the product are provided.

Wrong User Name

Please note that both the user name and license key are case-sensitive. Please make sure that you are using the user name which is specified in your license certificate email. If a license is registered in your company name, it will not work with your personal name.

No access to the original license e-mail

If you've lost the original license e-mail or you were not provided with this e-mail, please contact the sales team and we'll resend it.

A license key does not qualify for upgrade to a higher product version

If your license key does not work with the newly installed version of the software, please make sure that your current license key allows you to
upgrade for free to the latest version. If it does not, please contact sales in order to upgrade your license.

What to do if nothing helps

Don't panic! In some very rare cases license key can be generated for a name containing special Unicode characters that are not visible or cannot be correctly copy/pasted from the e-mail.

Contact support team by submitting a ticket with the original license certificate email and a screenshot of the IDE registration dialog displaying your user name and the license key in this dialog.