A Microsoft file hosting and synchronization service.
No, you haven't messed anything up. Google Photos and Microsoft OneDrive are separate services. Telling Google not to back up your photos will not turn off OneDrive syncing.
I suspect the two little lines that look like an H on your OneDrive cloud icon are actually a pause symbol. Does that look like this?
If so, according to Microsoft, two scenarios can cause the pause to kick in.
https://support.microsoft.com/en-gb/onedrive/how-to-pause-and-resume-onedrive-sync
To check if this is the case, right click on the cloud icon, resume sync, and then go to Settings. Then go to Sync and backup tab on the left, and check if those two settings are turned on. If they are turned on, you can turn them off.
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If your settings are already correct but OneDrive is still pausing regardless, this can be related to a potential emerging bug.
I’ve been seeing reports from other users over the past few weeks about OneDrive randomly pausing, sometimes when launching games or even web browsers.
You can temporarily turn off Windows Game Mode under Settings > Gaming > Game Mode to see if that makes any difference.
Another option is to uninstall your OneDrive and install this version: 26.189.0928.0009 (amd64).
To uninstall, go to Windows Settings > Apps > Installed Apps, locate OneDrive and uninstall it. Then restart the computer.
Then download and install it from here: https://oneclient.sfx.ms/Win/Installers/26.189.0928.0009/amd64/OneDriveSetup.exe
And I strongly suggest that you also file a report to make product team aware of this issue. Right click on the OneDrive icon on taskbar > Settings > Send a feedback.