A Microsoft file hosting and synchronization service.
Dear User,
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As far as I know, there are no restrictions on the number of files and subfolders that a single main folder can accommodate in OneDrive.
By the way, though there is no folder capacity limits in OneDrive, according to this support article **** Restrictions and limitations in OneDrive and SharePoint For optimum performance, we recommend syncing no more than a total of 300,000 files across your cloud storage. Performance issues can occur if you have more than 300,000 items, even if you are not syncing all items.
This means that when you sync OneDrive files and SharePoint files, it's recommended to sync less than 300,000 files. You can choose which folder to sync as described in this article Choose which OneDrive folders to sync to your computer
Additionally, the maximum file size (individual file) that can be uploaded to OneDrive for Business is 250 GB. If you exceed this limit, you will receive an error message.
It's also worth noting that OneDrive for Business is designed for individual use and not for team collaboration. If you're working with a team, it's recommended to use SharePoint instead.
I hope above helps!
Let me know if you have any concerns, I'll be glad to help you further.
Have a nice day!
Sincerely,
Tina | Microsoft Community Moderator