Hi JüriKolk,
We understand your concern and would like to help you resolve the issue.
If you are using Windows 10, then you can use the OneDrive app (as shown in the following screenshot) to sync your personal OneDrive files along with OneDrive for business and SharePoint online files,

If you do not have this sync client installed on your systems, please check the following article to install OneDrive sync client and to know how to use it to sync personal and business OneDrive files.
Get started with the new OneDrive sync client
in Windows
In the meantime, please provide the following information for further investigation.
- Which Operating system are you using?
- Please provide the screenshot of Programs and Features in Control Panel (Control Panel>Programs>Programs and Features), to confirm which OneDrive
sync client is installed.
- Right-click on the OneDrive sync client on the system tray, you’ll see the name of the sync client, please take the print screen (screenshot) and send it to us, like as shown below.

4. Please provide the screenshot of the error, If possible,
Thanks,
Neha