OneDrive sizes and dates don't match

OneDrive disk space and file size don't match

You may see a difference between Size and Size on Disk when viewing file, folder, or drive properties. This could be because of the following reasons:

1. The OneDrive Files On Demand feature doesn't download the file to your computer, only a placeholder or link to it.
2. Storage utilities show file categories, not the actual files.
3. Rounding differences in MB/GB calculations. OneDrive does not compress, change or modify your files when you upload them to OneDrive, but there are different ways to express the size of a file depending on the calculations used.

OneDrive folder and file dates don't match

You may see a difference between folder dates and content dates. This is because the folder date refers to when the folder itself was created or changed, not when something inside of it has changed. You may notice this when syncing an old folder from the cloud.

Files on Demand discrepancies

OneDrive Files On Demand doesn't download all the files to your computer, only a placeholder or link to it.

For more information, read about Files On-Demand for Windows 10 or Files On-Demand for Mac.

Offline files taking up space on macOS

The macOS Disk Utility and other apps display storage categories. In their support article, Apple say: 

"Don't rely on these categories to understand how much storage space is available for your data. 

"The Storage pane of About This Mac is the best way to determine the amount of storage space available on your Mac."

Get Info shows no size for macOS folders

File size information is only available for OneDrive files.