I've been experiencing this error ever since I updated my GOG launcher to the latest version... I have also tried uninstalling it completely (except for the "Games" folder); I removed all records of the launcher form both the registry, AppData, program data, and any remaining folders from the install location that remained behind after uninstalling.

Folders Remaining

GOG Install Locations
blob_storage
GPUCache
web

Program Data
GOG.com

App Data
GOG.com

So to be clear only the game folder reminded and no matter what I can not update the launcher past GOG Galaxy v1.2.59.21

I have tried all the suggestions found in this posting gog.com/forum/general/gog_galaxy_essential_components_error_2016_edition

Once the launcher is re-installed (v1.2.59.21); I left Gog.com in the Registry with only the (Default) Reg_SZ (value not set). I'm able to fully use the launcher but I have to refuse the update. Otherwise, I will get the error message and have to go back and remove all the previous mentioned folders and re-install v1.2.59.21

I can not jump to the current version or the 2.0 Beta following the removal of the aforementioned folders as I will immediately receive the error once the installation completes. Any assistance in upgrading to the current version or 2.0 would be greatly appreciated until then I'm stuck on version 1.2.59.21.