Preview/QuickView of HP Scan Pro PDF Files Causes System Crash in 10.5.5

Question

Ever since upgrading to 10.5.5 on my iMac Core 2 Duo 2.4GHz, I have been having problems with PDF files created by scanning documents using HP Scan Pro. Prior to 10.5.5, the PDFs from HP Scan Pro worked fine and behaved like any other PDF. Under 10.5.5, however, opening one in Preview or trying to view it in the Finder using QuickView causes the whole system to hang. Processor usage jumps to >100% and everything on the system becomes unresponsive. Every app causes a spinning beach ball, the Dock will not display, menus will not pull down, and I can't even call up the Force Quit dialog via the keyboard. There is nothing to be done but force-restart the system by holding down the power button.
Looking in the system.log, it seems that ATSServer is the process that is causing this problem. A dump of the relevent log entries is at the end of the message. The "Non-aligned pointer" and "Incorrect checksum" errors just continue forever until the point when I force a reboot.
Is anyone else experiencing this? Does anyone have knowledge of what changed in ATSServer or PDF handling in 10.5.5 that could be causing this? What is unique about the PDF files created by HP Scan Pro?
Thanks,
Drew
Sep 26 17:38:35 Work-iMac /System/Library/Frameworks/ApplicationServices.framework/Frameworks/ATS.framewo rk/Support/ATSServer[172]: FOExceptionMainHandler caught a fatal exception at 0x000f1f02
Sep 26 17:38:35 Work-iMac /System/Library/Frameworks/ApplicationServices.framework/Frameworks/ATS.framewo rk/Support/ATSServer[172]: FOExceptionMainHandler caught a fatal exception at 0x000f1502
Sep 26 17:38:36 Work-iMac /System/Library/Frameworks/ApplicationServices.framework/Frameworks/ATS.framewo rk/Support/ATSServer[172]: FOExceptionMainHandler caught a fatal exception at 0x000f1f44
Sep 26 17:38:36 Work-iMac /System/Library/Frameworks/ApplicationServices.framework/Frameworks/ATS.framewo rk/Support/ATSServer[172]: FOExceptionMainHandler caught a fatal exception at 0x000f1502
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xb0081000) malloc: * error for object 0x305f30: Non-aligned pointer being freed (2)\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac /System/Library/Frameworks/ApplicationServices.framework/Frameworks/ATS.framewo rk/Support/ATSServer[172]: FOExceptionMainHandler caught a fatal exception at 0x000f1693
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0x35b020: incorrect checksum for freed object - object was probably modified after being freed.\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac /System/Library/Frameworks/ApplicationServices.framework/Frameworks/ATS.framewo rk/Support/ATSServer[172]: FOExceptionMainHandler caught a fatal exception at 0x913cce78
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0x356da0: incorrect checksum for freed object - object was probably modified after being freed.\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0xd2c0c0: incorrect checksum for freed object - object was probably modified after being freed.\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36: --- last message repeated 5 times ---
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0x351fd0: incorrect checksum for freed object - object was probably modified after being freed.\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0x350850: incorrect checksum for freed object - object was probably modified after being freed.\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0x34ec60: incorrect checksum for freed object - object was probably modified after being freed.\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0xd2c0c0: incorrect checksum for freed object - object was probably modified after being freed.\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36: --- last message repeated 3 times ---
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0x32c5e0: incorrect checksum for freed object - object was probably modified after being freed.\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0x347d10: incorrect checksum for freed object - object was probably modified after being freed.\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0xd2c0c0: incorrect checksum for freed object - object was probably modified after being freed.\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0xd2c0c0: Non-aligned pointer being freed (2)\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0xd2c140: Non-aligned pointer being freed (2)\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0xd2c1c0: Non-aligned pointer being freed (2)\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0xd2c240: Non-aligned pointer being freed (2)\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0xd2c2c0: Non-aligned pointer being freed (2)\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0xd2c3c0: Non-aligned pointer being freed (2)\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0xd2c540: pointer being reallocated was not allocated\n* set a breakpoint in mallocerrorbreak to debug
Sep 26 17:38:36 Work-iMac ATSServer[172]: ATSServer(172,0xa023bfa0) malloc: * error for object 0xd2c540: Non-aligned pointer being freed (2)\n* set a breakpoint in mallocerrorbreak to debug

Answer 1

Thanks to everyone who has contributed to this thread that I started. I am glad to know it's not just me having these problems.
I have run through all the usual suggestions related to ATSServer problems and problematic fonts: I've cleared caches, checked all the fonts for broken ones, haven't installed any new ones since this problem began, etc., etc.
I've been able to make a few more observations about the problem in my case:
1. I don't get any crashes while using the HP Scanjet software. I can successfully create a PDF file.
2. The problem for me only exists on PDF files that I have had HP Scanjet do OCR on and save the text with the image in the PDF. If I scan to create an image-only PDF, it does not cause a problem.
3. I have now noticed that the problem comes not only when trying to open problem PDFs using Preview or QuickLook, but it also happens when mdsworker, the Spotlight indexer, tries to access the file for indexing. The computer then hangs. I have now had to turn off Spotlight until I can eliminate all the problem PDFs. (The problem only happens with PDFs created since the upgrade to 10.5.5. Older PDFs created with HP Scanjet that were in the Spotlight index earlier do not cause problems.)
4. These problem PDFs will open correctly in Adobe Acrobat or Acrobat Reader if Spotlight is off, but if Spotlight is on opening the file causes it to be indexed and the system hangs.
In Googling for solutions, I've found that people have sometimes been having problems with interaction between ATSServer and mdsworker since as far back as 10.2.x:
http://forums.appleinsider.com/archive/index.php/t-58103.html
http://www.macheist.com/forums/viewtopic.php?id=7406
http://blog.thebleacher.com/2008/01/02/the-runaway-atsserver-process/
http://installingcats.com/2008/05/06/mac-high-cpu-after-copying-pdf-books-atsser ver-mdworker/