Portable Chrome crashes instantly on 2 seperate machines.

Google Chrome 71.0.3578.80 (Official Build) (32-bit)
Revision 2ac50e7249fbd55e6f517a28131605c9fb9fe897-refs/branch-heads/3578@{#860}
OS Windows
JavaScript V8 7.1.302.28
Flash
User Agent Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.80 Safari/537.36
Command Line "E:\Portable apps\PortableApps\GoogleChromePortable\App\Chrome-bin\chrome.exe" --user-data-dir="E:\Portable apps\PortableApps\GoogleChromePortable\Data\profile" --disk-cache-dir="C:\Users\malhe\AppData\Local\Temp\GoogleChromePortable" --flag-switches-begin --flag-switches-end
Executable Path
Profile Path
Variations
Portable Apps Platform 16 2018-12-06

Hi all,
Since 10th December I have experienced odd behaviour from recently updated Chrome Portable on 2 seperate computers ( OS 8.1 and 10) running portable apps Chrome.
Upon launch a series of sidebars pop up announcing various extensions have crashed. Chrome then becomes unable to access any url. The about: query allows access to the app general information (see above), but most other about: commands do nothing or hang.
The exact same behaviour now manifests on a second, seperate computer using Portable apps Chrome.
I have managed to salvage my bookmarks (labouriously one at a time) from one machine and eventually had to uninstall Chrome and reinstall via portable apps platform.
Upon reinstall the new instance simply crashed upon launch (no side popups this time because no extensions). All other portable apps are working fine, Firefox is working fine, so I still have a browser.
I have not repeated the uninstall/reinstall on the O/S 8.1 machine as it has been in use much longer and my Chrome browser has a load of stuff I don't want to lose, so I'm hoping someone has a fix that doesn't involve losing the browsers data.
I have run AV, Rootkit, malware, chkdsk etc scans on both machines just in case. Both return no result and nothing else is affected in the portable apps platform.
Any help greatly appreciated.
Cheers