Microsoft is working on a fix for a problem with one of this month's Patch Tuesday updates, which saw certain OpenType fonts made unreadable in PowerPoint and other applications.
The update in question was designed to fix a remote code execution vulnerability that could have affected people visiting pages with embedded TrueType or OpenType fonts. It seems to have fixed that problem, but caused another.
One complaint on a Microsoft forum stated that Quark Xpress and Coreldraw on Windows 7 and XP had become unable to render OpenType characters larger than 15pt. The poster said 330 machines had the same problem, which could be fixed by uninstalling the patch — hardly an ideal solution, given the severity of the flaw.
However, Microsoft has said it is aware of the issue.
"We are aware of issues related to OpenType Font (OTF) rendering in applications such as PowerPoint on affected versions of Windows that occur after this security update is applied," it said in a note. "We are currently investigating these issues and will take appropriate action to address the known issues."
The 11 December Patch Tuesday updates also included fixes for Internet Explorer, Exchange and the Surface RT tablet.