Effective September 1, 2016, we have begun displaying a warning to all Slate users who have the Grammarly browser extension installed.

Grammarly is known to cause serious corruption to messages and documents created or updated using web-based HTML editors, such as those throughout Slate. For example, a message created or edited in Deliver is typically 5-15 kilobytes; when the Grammarly extension has been installed by a user, it manipulates the HTML and increases the size to more than 2,000 kilobytes through the injection of hidden CSS and JavaScript code. This is a serious issue that affects most web-based HTML editors and is not specific to Slate. The resultant HTML is likely to be clipped or blocked by Gmail and other email service providers.

As a result of the serious issues associated with Grammarly, we have taken the following steps:

1. A warning will be displayed on all administrative pages within Slate to all Slate users who have the Grammarly browser extension installed. This warning will not disappear until the extension has been disabled or uninstalled.

2. We are preventing mailings that have HTML contents corrupted by Grammarly from being activated.

3. We have scrubbed all corruption caused by Grammarly from existing mailings. This has not changed the visual appearance of the mailings, as the Grammarly code that was injected was invisible.

We have also removed Grammarly code from form and event descriptions and notes, as well as trip notes. We will be taking further steps to remove Grammarly code that has been added to XSLT files and configuration files such as base.xml, as we have observed application landing pages being bloated from 50 kilobytes to more than 2,000 kilobytes as a result of the modifications made by Grammarly.

If Grammarly is able to correct their browser extension such that it no longer corrupts the contents of web-based HTML editors, we will seek to re-allow this browser extension. At the current time, however, the serious issues this browser extension causes has warranted these actions.

Grammarly Support: Uninstall Grammarly browser extension