A Microsoft file hosting and synchronization service.
The brown file box overlay on the OneDrive files indicate you have set OneDrive settings to 'Files on Demand', that setting causes the files to be uploaded to OneDrive online and removed from your PC to save space and the brown box indicates OneDrive is currently not syncing correctly.
Open OneDrive settings, then stop OneDrive syncing, wait for a few seconds, then start OneDrive syncing again and wait for that process to complete.