What is the MR cookie?
MR is an HTTP cookie set by Microsoft, usually when a website embeds Bing services (search, maps, widgets) or analytics and advertising tools from the Microsoft/Bing Ads ecosystem. The cookie appears on the bing.com domain as soon as the browser loads a Microsoft-hosted resource on the visited page.
It belongs to the family of cookies Microsoft uses to measure user behavior on pages that include Bing content or scripts, acting as a third-party cookie from the perspective of the site displaying it.
What data it stores
MR stores an identifier generated by Microsoft's servers, used to correlate requests coming from the same browsing session or browser. The exact value format is not publicly documented by Microsoft and may vary.
Data collected through this cookie is sent to Microsoft's servers (bing.com domain), where it is aggregated for analytics and service optimization purposes.
What it is used for
The stated purpose is statistical: Microsoft uses MR to determine whether requests from the same user need to be refreshed or resumed, contributing to measuring the performance and effectiveness of pages that use Bing resources.
For site administrators, the presence of this cookie usually indicates an integration with Microsoft services (Bing Maps, Bing Search widget, Microsoft Advertising/UET) and does not offer direct control over the collected data.
Does it require consent?
MR is classified as a statistics (analytics) cookie and is not strictly necessary for the website to function. Under GDPR (Regulation 2016/679) and the ePrivacy Directive (transposed in Romania via Law 506/2004), this cookie may only be set after obtaining the visitor's explicit consent.
- Site administrators must disclose it in the cookie policy, under the statistics category.
- The script generating it must be blocked until consent is given.
- Consent must be revocable at any time, as easily as it was granted.
How to block or delete MR
Visitors can delete or block MR through their browser settings (cookies and site data section) or use dedicated tracking-blocker extensions. Blocking it does not affect a site's core functionality, only certain embedded Bing features.
For site administrators, the most effective way to block it automatically before consent is a CMP like CookieFix, which stops Microsoft/Bing scripts from loading until the visitor accepts the statistics category.
Frequently asked questions
It is not considered dangerous, but it collects behavioral data for statistical purposes, which is why it requires visitor consent under GDPR.
Its typical duration is 7 days, after which it automatically expires in the browser.
It is a third-party cookie, set by Microsoft on the bing.com domain when the visited site embeds Bing resources.
Yes, any site using it must disclose it under the statistics category, along with its purpose and duration.