Thank you for your helpful assistance and useful information and links.
The affected Win10 host computer has MS Defender in use. I made 'simple update' to update host 188.8.131.52 and lost connection afterwards. Had to install previous host on-site. Follow your suggestions next time I'll be there.
I like to install Remote Utilities Host 184.108.40.206 on Bitdefender Total Security protected computer(s) too. Setting Remote Utilities program folder (x86) and other folders to Bitdefender exceptions doesn't help. Today I reported file 'host220.127.116.11.exe' and 'host18.104.22.168.msi' as False Positiv to Bitdefender. Let's see if we can successfully install Remote Utilities host in 72 hours as promised by Bitdefender.
Today I was able to successfully update from Host 22.214.171.124 to Remote Utilities Host 126.96.36.199 at the Host computer itself using file 'host188.8.131.52.exe' instead of file 'host184.108.40.206.msi'. Everything works perfect now and you can forget about the issue. By the way I used [censored] before, but the [censored] Business license is to expensive to manage one single host machine. I'm happy with Remote Utilities software and community.
Thank you for your answer. Yes, I'm unable to update the remote Host (220.127.116.11) using the 'Simple update' option and manually by installing Host 18.104.22.168 on the Host machine (Microsoft Windows Server Standard 2012 R2) As soon as I manually install Host 22.214.171.124 again, everything works. I'll check Remote Utilities service tomorrow after manually installing Host version 126.96.36.199 again. Don't think too much about it. I can life with Viewer 188.8.131.52 and Host 184.108.40.206 (I need to transfer some files from the host to the viewer every day).
Sorry, The name is "MicrosoftProgram_Install_and_Uninstall.meta.diagcab" This is really a very good tool from Microsoft. (Cabinet file of problem handling). Double klick the little cabinet file and you will no longer need to search for the missing msi file.