Although we already have a knowledge base article about this topic, it’s come up 3 times this week from customers, so it seems like a good candidate for some extra attention in the blog.

FogBugz gives each case a unique case number—unique for that installation that is.  FogBugz handles incoming email by either creating a case if one does not exist, or by appending the new email to an existing case.  It uses the number in the subject line to determine which case to add the new email to.  With this fact you can probably see the contours of a possible problem.

Given the growing number of FogBugz installations out there, case numbers can “clash.”  By that I mean that if I have an installation that sends an email with case 100 in the subject line, and the recipient installation also has a case 100 (more than likely having nothing to do with the original case 100), then the email gets appended to the wrong case, and confusion can ensue.

There is an easy solution for this, one we use here at Fog Creek, and that is to add a prefix to your case numbers in emails.

You’ll want to pick some set of letters that you think will be unique, or at least rare—we use “FC” here.  Then alter the sCasePrefix variable.  In a Windows installation make a registry entry at HKLM\Software\Fog Creek Software\FogBugz\[path to your install]\sCasePrefix

In a Unix installation make a value in the application.data file (fogbugz/Accessories folder) called sCasePrefix

Then you’re all set.  You’ll be merrily emailing between installations with no clashes between the cases.  The actual case numbers will not be altered in your installation, so case 100 remains case 100—the prefix is only added to emails sent out from your FogBugz installation.