Any particular reason for running the Beta pre-release build?

One thing that I found in common for two of those crash reports was aswhooka.dll a module being red flagged under modules. That file is described as malware / malicious on the web in a number of places, by different sources. http://immuneyourpc.com/uninstall-aswhooka-dll-malware-removal-guide/ While another mention was it being part of Avast Behavior Shield. https://www.bleepingcomputer.com/forums/t/648520/am-i-infected-avast-aswhookadll/ And this refers to that file as a "virus". https://www.removemalwarefrompc.com/uninstall-aswhooka-dll-virus-easily

I don't know what to recommend and if that will fix your crashing problem. Please see these two Knowledge Base articles for guidance. https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware https://support.mozilla.org/en-US/kb/how-stay-safe-web

I tried to uninstall the Beta. It demanded administrator privileges. I wasn't sure about that, and read a post that I should reinstall it to get rid of the old one, and am now running 58.0.2. It unfortunately continues to crash.

I turned off Avast webshield, ran MalwareFox per one of your posts. It seemed like it was better for a bit after the new FF install, then went back to crashing. crash reports are as follows: bp-e9d21088-269b-4dae-ad11-4f1a00180212 bp-1b508abe-5065-4a82-af01-27ce01180212 bp-9c0aed1f-105b-4887-a1cd-c42231180212 bp-30431875-b3b6-4764-aed8-54da01180212 bp-0a42804e-c222-46df-a342-0264a1180211

-Karl

You may have ad/mal-ware. Further information can be found in this article; https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

Those crash reports are OOM (out-of-memory) reports where not enough free memory is available.

You can try to modify multi-process settings to see if this has effect.

• set number of content processes to 1 if it is currently set to a higher value (4)
  Options/Preferences -> General -> Performance
  remove checkmark: [ ] "Use recommended performance settings"

• https://support.mozilla.org/en-US/kb/performance-settings