David Anders,The Computer Guy, a freelance systems engineer in Seattle, WA.
Resolves computer problems, assists with production issues, designs and installs networks.
Type 11 errors and Mac OS 7.6.1 Type 11 (and "FPU not installed") error messages should be sharply reduced in Mac OS 7.6.1. Here's why:
Prior to Mac OS 7.6.1, "most crashes in native code previously were mapped to the 'miscellaneous fatal error' code which is 11. The software will now calculate the real error code and report the correct number."
"Also, previously, a type 11 error when MacsBug is not installed would cause a 'Sorry, a system error has occurred' dialog and force an immediate reboot. Now most of these cases will instead 'unexpectedly quit' the foreground application." It is probably still best to restart after this occurs, but you won't be required to do so anymore.
For those of you not using 7.6.1 yet...Type 11 and "No FPU Installed" system errors Type 11 and "No FPU Installed" system errors have become surprisingly common for Power Mac users (especially after upgrading to System 7.5.1 or later), making it one of the most asked-about problems today. The ultimate cause of these errors is almost always bugs in application software. So you cannot really "fix" these errors yourself. Still, there are a number of quasi-fixes that can help eliminate or reduce the chances of getting these errors. In particular, here's a complete list of things to try:
Restart. The error may not occur again any time soon.
If the error occurs only or mainly with one application, and especially if you can reproduce it consistently, a bug in that program is the likely cause. Contact the vendor for compatibility information.
One special note: Power Mac versions of Microsoft Office applications (Word 6 and Excel 5) can lead to Type 11 errors, most often when also using virtual memory and/or QuickDraw GX. To fix this, you should install the Office4.2x Update for Power Mac extension (mc1164.hqx at Microsoft's web site; it is now up to version 1.0.1). If you use System 7.5.2, also get Microsoft's Office Manager Patch for 7.5.2 (mompatch.hqx, also known as mc1265.hqx, at Microsoft's web site). The Office Manager Patch, as its name implies, is not needed if you upgrade to System 7.5.3 (despite the contrary advice in the Read Me files that come with System 7.5 Update 2.0). Microsoft also asserts that the Office Update extension is only needed if you are running QuickDraw GX. In general, Microsoft Office 4.2.1b incorporates these fixes, making the separate updates unnecessary. Still, due to all of this confusion about what is and is not needed, you may want to experiment here. If problems persist, consider dumping the MOM control panel altogether. It has been implicated in problems with shutting down the Mac.
Speaking of System 7.5 Update 2.0, if you use a version of System 7.5 prior to System 7.5.3, install this Update. It has numerous bug fixes, several of which Apple reports will reduce the number of Type 11 errors you should get (though some unfortunate users have reported that it increases their error rate!).
Zap the PRAM. Some Type 11 errors may be caused by corrupted PRAM.
Update the disk driver to the latest available version (especially because some older drivers are incompatible with SCSI Manager 4.3, which is used by System 7.5). Be sure to use Drive Setup rather than HD SC Setup, if your Mac model is one that can use it (all Power Macs can).
Turn off Modern Memory Manager. It may trigger Type 11 errors in situations that would be ignored by the "old" Memory Manager.
Check for extension conflicts. Turn off conflicting extensions (or get an upgrade that fixes the problem, if such an upgrade exists). Some known possibilities include: QuickDraw GX, ATM, SuperATM.
Too many fonts in the Fonts folder can cause Type 11 errors. To check for this, remove the Fonts folder from the System Folder temporarily and see if the error disappears.
Corrupted fonts can also cause Type 11 errors. If removing the Fonts folder eliminates the problem, use a utility like Font Box to check for corrupted fonts.
Incompatible 680x0 software may be a cause. Upgrade to Power Mac native versions if possible.
Do a clean install of your system software. The software may have gotten corrupted.
Consider increasing the size of your system heap, via options available in utilities such as Now Startup Manager or Conflict Catcher 3. For example, if you don't have enough heap space to load a shared library, a Type 11 error may occur.
If you are still desperate for a cure, disconnect any external SCSI devices to see if that helps. If so, there
may be a problem or incompatibility with the external hardware or cables.
Defective memory (SIMMs/DIMMs) can cause seemingly random Type 11 errors.
Defective RAM cache cards are a known source of Type 11 errors in Power Macs. This is especially a problem for RAM caches cards that shipped with early Power Mac 8100/80s as well as with third-party RAM cache for PCI-based Power Macs.
If the errors continue after all of this, particularly if they occur while in the Finder, there may be a hardware problem with the logic board itself. Take it in for service.
Finally, here's a bit of technical background on why these errors have become so common: On Power Macs, it turns out that Type 11 errors can occur after almost any type of system error (bus error, address error, etc.), as long as the error occurs while the Mac is running native code. On the other hand, No FPU Installed errors (which are functionally the same as Type 10 errors) occur under two main conditions: (a) The Power Mac is running in emulation mode. Essentially, since the Power Mac's emulator does not have a FPU (floating point unit), an error occurs if any 680x0 program includes instructions to call the FPU. This can also happen if a program somehow mistakenly executes data and interprets it as a call for the FPU. (b) The
Mac can't determine the correct error situation, when running either in emulation or native mode. More specifically, Apple has stated: "A number of errors are occurring simultaneously. They eventually percolate out as an "FPU not installed" error. An error did occur, but it has nothing whatsoever to do with the need for a floating point unit."
Overall, errors that would have resulted in an address error (Type 1 error) or even no error at all on a 680x0 Mac, will more likely cause Type 11 or "No FPU Installed" errors on Power Macs.
By the way, Sad Macs stated that Type 11 errors may be indirectly due to corruption of the 680x0 emulator as it loads in to RAM. I had originally gotten this tidbit from an Apple Tech Note, but Apple doesn't seem to emphasize this anymore.
Type 11 errors in Netscape and other Internet software when connected via PPP with Open Transport An Open Transport has been described by AOL - and AOL's OpenOT extension is designed to fix it. (OpenOT is currently only available as part of the AOL 3.0 software.) The problem, however, is by no means restricted to AOL software. It more generally affects FreePPP and any other similar MDEV that is not OT-native.