Thanks for the clear, concise instructions, Linc - I greatly appreciate it.
The Console log showed a series of these, with the same type of error messages with other pid #'s starting well before the incident and continuing well after, though I noticed no other obvious user issues, and no hardware tests have detected any issues:
7/2/15 11:23:19.518 AM ReportCrash[1378]: Attempt to read info_array in pid 1397 failed, address was 7fff64be3fa8 (repeated six times)
7/2/15 11:23:19.570 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent[1397]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:23:19.570 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent) Throttling respawn: Will start in 10 seconds file:///Users/***/Library/Logs/DiagnosticReports/LoaderAgent_2015-07-02-112018_ *-iMac.crash
Here are the excerpts leading up to the first mention of Firefox, which is what caused the hang, and from here on I copied everything (except the duplicated “Attempted to read(s)...”). I removed user info and subbed asterisks:
7/2/15 11:23:39.664 AM ReportCrash[1401]: Attempt to read info_array in pid 1404 failed, address was 7fff61d4afa8
7/2/15 11:23:39.671 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent[1404]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:23:39.671 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent) Throttling respawn: Will start in 10 seconds
7/2/15 11:23:39.673 AM ReportCrash[1401]: Saved crash report for LoaderAgent[1404] version ??? to /Users/***/Library/Logs/DiagnosticReports/LoaderAgent_2015-07-02-112339 *-iMac.crash
7/2/15 11:23:39.677 AM ReportCrash[1401]: Removing excessive log: file:///Users/***/Library/Logs/DiagnosticReports/LoaderAgent_2015-07-02-112018 *-iMac.crash
7/2/15 11:23:40.184 AM ReportCrash[1395]: Attempt to read info_array in pid 1408 failed, address was 7fff5fd46f58
7/2/15 11:23:40.192 AM com.apple.launchd[1]: (com.avg.avgnotifyd[1408]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:23:40.192 AM com.apple.launchd[1]: (com.avg.avgnotifyd) Throttling respawn: Will start in 10 seconds
7/2/15 11:23:40.192 AM ReportCrash[1395]: Saved crash report for avgnotifyd[1408] version ??? to /Library/Logs/DiagnosticReports/avgnotifyd_2015-07-02-112340_*-iMac.crash
7/2/15 11:23:42.156 AM com.apple.launchd.peruser.501[213]: (org.mozilla.firefox.10592[1332]) Exited: Terminated: 15
7/2/15 11:23:45.959 AM ReportCrash[1395]: Attempt to read info_array in pid 1414 failed, address was 7fff61116f60
7/2/15 11:23:45.965 AM com.apple.launchd[1]: (com.avg.avgconfigd[1414]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:23:45.965 AM com.apple.launchd[1]: (com.avg.avgconfigd) Throttling respawn: Will start in 10 seconds
7/2/15 11:23:45.967 AM ReportCrash[1395]: Saved crash report for avgconfigd[1414] version ??? to /Library/Logs/DiagnosticReports/avgconfigd_2015-07-02-112345_*-iMac.crash
7/2/15 11:23:48.116 AM spindump[1405]: Saved hang report for firefox version 38.0.5 (3815.5.25) to /Library/Logs/DiagnosticReports/firefox_2015-07-02-112348_*-iMac.hang
7/2/15 11:23:49.675 AM ReportCrash[1401]: Attempt to read info_array in pid 1422 failed, address was 7fff67332fa8
7/2/15 11:23:49.681 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent[1422]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:23:49.681 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent) Throttling respawn: Will start in 10 seconds
7/2/15 11:23:49.683 AM ReportCrash[1401]: Saved crash report for LoaderAgent[1422] version ??? to /Users/***/Library/Logs/DiagnosticReports/LoaderAgent_2015-07-02-112349_*.crash
7/2/15 11:23:49.686 AM ReportCrash[1401]: Removing excessive log: file:///Users/***/Library/Logs/DiagnosticReports/LoaderAgent_2015-07-02-112028_ *-iMac.crash
7/2/15 11:23:50.198 AM ReportCrash[1395]: Attempt to read info_array in pid 1423 failed, address was 7fff6cc19f58
7/2/15 11:23:50.216 AM com.apple.launchd[1]: (com.avg.avgnotifyd[1423]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:23:50.216 AM com.apple.launchd[1]: (com.avg.avgnotifyd) Throttling respawn: Will start in 10 seconds
7/2/15 11:23:50.218 AM ReportCrash[1395]: Saved crash report for avgnotifyd[1423] version ??? to /Library/Logs/DiagnosticReports/avgnotifyd_2015-07-02-112350_*-iMac.crash
7/2/15 11:23:52.404 AM SubmitDiagInfo[1424]: Running in single report mode to submit: file:///Library/Logs/DiagnosticReports/firefox_2015-07-02-112348_*-iMac.hang
7/2/15 11:23:55.970 AM ReportCrash[1395]: Attempt to read info_array in pid 1430 failed, address was 7fff61725f60
7/2/15 11:23:55.976 AM com.apple.launchd[1]: (com.avg.avgconfigd[1430]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:23:55.976 AM com.apple.launchd[1]: (com.avg.avgconfigd) Throttling respawn: Will start in 10 seconds
7/2/15 11:23:55.977 AM ReportCrash[1395]: Saved crash report for avgconfigd[1430] version ??? to /Library/Logs/DiagnosticReports/avgconfigd_2015-07-02-112355_*-iMac.crash
7/2/15 11:23:59.757 AM ReportCrash[1401]: Attempt to read info_array in pid 1445 failed, address was 7fff638f9fa8
7/2/15 11:23:59.763 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent[1445]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:23:59.763 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent) Throttling respawn: Will start in 10 seconds
7/2/15 11:23:59.764 AM ReportCrash[1401]: Saved crash report for LoaderAgent[1445] version ??? to /Users/***/Library/Logs/DiagnosticReports/LoaderAgent_2015-07-02-112359_*-iMac. crash
7/2/15 11:23:59.767 AM ReportCrash[1401]: Removing excessive log: file:///Users/***/Library/Logs/DiagnosticReports/LoaderAgent_2015-07-02-112038_ *-iMac.crash
7/2/15 11:24:00.220 AM ReportCrash[1395]: Attempt to read info_array in pid 1450 failed, address was 7fff630fcf58
7/2/15 11:24:00.252 AM com.apple.launchd[1]: (com.avg.avgnotifyd[1450]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:24:00.252 AM com.apple.launchd[1]: (com.avg.avgnotifyd) Throttling respawn: Will start in 10 seconds
7/2/15 11:24:00.253 AM ReportCrash[1395]: Saved crash report for avgnotifyd[1450] version ??? to /Library/Logs/DiagnosticReports/avgnotifyd_2015-07-02-112400_*iMac.crash
7/2/15 11:24:02.268 AM SubmitDiagInfo[1424]: Submitted hang report: file:///Library/Logs/DiagnosticReports/firefox_2015-07-02-112348_*-iMac.hang
7/2/15 11:24:05.980 AM ReportCrash[1395]: Attempt to read info_array in pid 1456 failed, address was 7fff66b36f60
7/2/15 11:24:05.986 AM com.apple.launchd[1]: (com.avg.avgconfigd) Throttling respawn: Will start in 10 seconds
7/2/15 11:24:05.988 AM ReportCrash[1395]: Saved crash report for avgconfigd[1456] version ??? to /Library/Logs/DiagnosticReports/avgconfigd_2015-07-02-112405_*-iMac.crash
7/2/15 11:24:09.829 AM ReportCrash[1401]: Attempt to read info_array in pid 1458 failed, address was 7fff5fe75fa8
7/2/15 11:24:09.835 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent[1458]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:24:09.835 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent) Throttling respawn: Will start in 10 seconds
7/2/15 11:24:09.837 AM ReportCrash[1401]: Saved crash report for LoaderAgent[1458] version ??? to /Users/***/Library/Logs/DiagnosticReports/LoaderAgent_2015-07-02-112409_*-iMac. crash
7/2/15 11:24:09.841 AM ReportCrash[1401]: Removing excessive log: file:///Users/*/Library/Logs/DiagnosticReports/LoaderAgent_2015-07-02-112048_*- iMac.crash
7/2/15 11:24:10.257 AM ReportCrash[1395]: Attempt to read info_array in pid 1459 failed, address was 7fff665caf58
7/2/15 11:24:10.257 AM ReportCrash[1395]: Attempt to read info_array in pid 1459 failed, address was 7fff665caf58
7/2/15 11:24:10.263 AM com.apple.launchd[1]: (com.avg.avgnotifyd) Throttling respawn: Will start in 10 seconds
7/2/15 11:24:10.264 AM ReportCrash[1395]: Saved crash report for avgnotifyd[1459] version ??? to /Library/Logs/DiagnosticReports/avgnotifyd_2015-07-02-112410_*-iMac.crash
7/2/15 11:24:15.990 AM ReportCrash[1395]: Attempt to read info_array in pid 1460 failed, address was 7fff6155ef60
7/2/15 11:24:15.997 AM com.apple.launchd[1]: (com.avg.avgconfigd[1460]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:24:15.997 AM com.apple.launchd[1]: (com.avg.avgconfigd) Throttling respawn: Will start in 10 seconds
7/2/15 11:24:15.998 AM ReportCrash[1395]: Saved crash report for avgconfigd[1460] version ??? to /Library/Logs/DiagnosticReports/avgconfigd_2015-07-02-112415_*-iMac.crash
7/2/15 11:24:19.912 AM ReportCrash[1401]: Attempt to read info_array in pid 1461 failed, address was 7fff68cacfa8
7/2/15 11:24:19.919 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent[1461]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:24:19.919 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent) Throttling respawn: Will start in 10 seconds
7/2/15 11:24:19.921 AM ReportCrash[1401]: Saved crash report for LoaderAgent[1461] version ??? to /Users/***/Library/Logs/DiagnosticReports/LoaderAgent_2015-07-02-112419_*-iMac. crash
7/2/15 11:24:19.925 AM ReportCrash[1401]: Removing excessive log: file:///Users/***/Library/Logs/DiagnosticReports/LoaderAgent_2015-07-02-112058_ *-iMac.crash
7/2/15 11:24:20.331 AM ReportCrash[1463]: Attempt to read info_array in pid 1462 failed, address was 7fff6ccecf58
7/2/15 11:24:20.336 AM ReportCrash[1463]: DebugSymbols was unable to start a spotlight query: spotlight is not responding or disabled.
7/2/15 11:24:20.340 AM com.apple.launchd[1]: (com.avg.avgnotifyd[1462]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:24:20.340 AM com.apple.launchd[1]: (com.avg.avgnotifyd) Throttling respawn: Will start in 10 seconds
7/2/15 11:24:20.372 AM ReportCrash[1463]: Saved crash report for avgnotifyd[1462] version ??? to /Library/Logs/DiagnosticReports/avgnotifyd_2015-07-02-112420 *-iMac.crash
7/2/15 11:24:26.001 AM ReportCrash[1463]: Attempt to read info_array in pid 1464 failed, address was 7fff61ce0f60
7/2/15 11:24:26.008 AM com.apple.launchd[1]: (com.avg.avgconfigd[1464]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:24:26.008 AM com.apple.launchd[1]: (com.avg.avgconfigd) Throttling respawn: Will start in 10 seconds
7/2/15 11:24:26.010 AM ReportCrash[1463]: Saved crash report for avgconfigd[1464] version ??? to /Library/Logs/DiagnosticReports/avgconfigd_2015-07-02-112426_*-iMac.crash
7/2/15 11:24:29.990 AM ReportCrash[1466]: Attempt to read info_array in pid 1465 failed, address was 7fff6732ffa8
7/2/15 11:24:30.020 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent[1465]) Job appears to have crashed: Trace/BPT trap: 5
7/2/15 11:24:30.020 AM com.apple.launchd.peruser.501[213]: (com.avg.LoaderAgent) Throttling respawn: Will start in 10 seconds
7/2/15 11:24:30.052 AM ReportCrash[1466]: Saved crash report for LoaderAgent[1465] version ??? to /Users/***/Library/Logs/DiagnosticReports/LoaderAgent_2015-07-02-112430_*-iMac. crash
7/2/15 11:24:30.056
AM ReportCrash[1466]: Removing excessive log:
file:///Users/***/Library/Logs/DiagnosticReports/LoaderAgent_2015-07-02-112108_* -iMac.crash.
I hope this helps. If you need additional information, please advise - thanks again.