The first thing you should do if you discover that a master key has gone missing is call Anderson Lock.

Anderson Lock’s service department recently rekeyed three unrelated facilities, in Chicago and surrounding suburbs, that reported “missing master keys.”

Police responded to multiple reports of thefts, but found no evidence of forceful entry. Their report pointed to “access gained through the use of an unauthorized master key.”

When any key is lost or stolen there is a risk of theft or vandalism until the lock(s) that are operated by that key are re-secured. If a master key goes missing the threat of loss is greatly multiplied.

A quick online search of the term “Missing Master Key” produced dozens of articles referencing the cost of rekeying commercial, educational and multi-residential buildings at tens and even hundreds of thousands of dollars, depending on the size of the system.

A 2019 Chicago Sun-Times news headline reported: “Master keys for O’Hare Airport security access were lost, costing city in ‘five figures’. The article, by Robert Herguth, stated that, “A set of keys that provides almost total access to O’Hare Airport were lost and never recovered.” The keys locked and unlocked perimeter fences and other key entry points.

The article further stated that the security officer who lost the keys was fired, and that, “Officials with the aviation department…say that, despite the loss of the keys, security at O’Hare wasn’t compromised because they instituted an ‘elevated security posture,’ with additional security officers at critical ‘access points’ until all of the locks and keys were replaced.”

In 2022, every lock in the state capitol building in Hawaii needed to be rekeyed, at a cost of $250,000, because a master key had gone missing.

Another news article, from 2016, with the headline, “Master Key Loss Costs College More than $500,000” describes a missing master key at the College of William and Mary.

A Master Key System allows for various levels of restricted entry to different areas of a building, or buildings, and it enables two or more keys to open one lock. The top key in the system hierarchy, often referred to as a GMK (Grand Master Key) or GGMK (Great Grand Master Key) opens all the locks in that Master Key System. If a GMK or GGMK is stolen or lost, every lock and key in that system must be changed to assure security.

The “missing master key” at the suburban Chicago multi-residential complex, referenced above, did have a GGMK, several GMK’s, and hundreds of Change Keys (the individual keys that open individual locks).

Fortunately, it was not all bad news for this facility…the locks all contained interchangeable cores (IC). Small format interchangeable cores (SFIC), are standardized among lock manufacturers, as illustrated above with SFIC cores from Best Locks, Falcon and Schlage. Locks with SFIC cores don’t require disassembly in order to change the cylinder. The figure-8 IC can be rapidly removed and replaced in the field via the use of a specialized “control key”.

SFIC’s are readily adapted for master keying systems, and can be set up with spare cores and keys for quick replacement, such as when a personnel change takes place. Extracted cores can be re-combinated at a lock shop without urgency and placed back into maintenance storage for future use.

However, when the lost or stolen master key is part of a large system, there are not enough “spare” cores and keys to change all of the compromised locks.

A lock like this, that is operated with an interchangeable core, would not have to be removed from the door to be rekeyed. The SFIC cylinder could be removed and replaced with a new cylinder, operated by a new key.

In that scenario Anderson Lock creates a new Master Key System and combinates new SFIC cylinders, cuts new keys, then removes existing cores, and installs the new cores. This may be done for one floor of a large building, or one building of a large campus, or a percentage of the total number of locks. The compromised cores are brought back to Anderson Lock to be rekeyed. New keys are cut to operate the re-combinated cores, and they are inserted into the next batch of compromised locks the next day.

Occasionally, a complete existing lock will have to be replaced, however, the cost for new IC cores, keys and the labor involved in creating and installing a new Master Key System is much less than replacing ALL of the locks. SFIC cylinders have a higher initial cost than standard cylinders, nonetheless, they are worth the investment in security, convenience and re-keying.

In addition to standard key-in-knob or lever locks, SFIC housings are also manufactured for rim and mortise cylinders, padlocks, cabinet locks and electrical switches.

Dave Satterthwaite, one of our experienced lock techs, notes that IC cylinders are particularly advised for installation into rim exit devices because if a standard rim cylinder needs to be rekeyed the whole device must be removed from the door, incurring higher labor charges. With IC cylinders, the core is easily removed, rekeyed and replaced, in just a few minutes.

As airports, retail chains, universities, government buildings and multi-residential facilities have learned, a missing master key creates a serious breach of security, costs a lot of money, and the process of replacing, or rekeying cylinders and distributing new keys is time-consuming.

Q. Are Master Key Systems worth the worry of having a master key go missing?

A. Yes!

Master Key Systems have stood the test of time for creating convenience and affordable access control. Master keys enhance security by allowing facility owners or managers to restrict access to certain areas, thus giving greater control over who can go where. Plus, a Master Key System is highly customizable. For example, a small business owner can choose to have a single master key that opens all the locks in the system; sub-master keys for some personnel; and single-use keys for others.

But what if a master key does go missing?

Call Anderson Lock! We’ve been designing, installing and maintaining Master Key Systems since 1960. Our MK experts; our large team of trained, bonded, and skilled lock technicians; our huge inventory of key blanks; as well as high security, SFIC, and standard cylinders from several manufacturers; makes us uniquely qualified to respond quickly to every “missing master key” crisis.