For many years, the term “out-of-band Microsoft update” meant that Microsoft was releasing a special patch for a security issue identified as being under active attack. The patch was urgent enough to be released outside the normal “Patch Tuesday” security updates released the second Tuesday of every month.
But recently Microsoft has been releasing out-of-band updates that fix issues that were introduced with the monthly security updates. Often people install the monthly security updates without realizing that there are additional ways that Microsoft fixes issues introduced by its patches.
