In the root folder of the USB stick, when I click on the usual START icon for PortableApps, I get this warning:
The PortableAppsPlatform.exe file is not a valid PortableApps.com release and can not be launched.
Yet when I go into the PortableApps folder, then go into PortableApps.com and click on PortableAppsPlatform.exe, the application starts.
BUT, having opened, I get the error box:
The PortableApps.com Updater or App Directory is already running. This could be the PortableApps.com Platform automatically checking for updates on startup. Please wait for other instances to finish before starting another.
The very same thing occurs to other copies of PortableApps that I have been maintaining, including one saved on the hard drive of my laptop.
I tied reinstalling PortableApps, but it complained that the my USB stick, with approximately 8GB of free space, did not have enough memory.