Since upgrading to Windows 11, all of the offline Smart Sync files in Dropbox have an ugly brown icon on the lower left, instead of the light gray X I had in Windows 10.
After a couple of people asked about it and had it on their offline OneDrive files, I dug a little deeper.
- I knew the files with the icon were offline – the file properties showed the file size as 0 byte. This is correct for offline files as the file on the hard drive is a link to the online file.
- Google searches turned up several questions asking what the icon was, but the best guess was the file attributes were corrupt. I checked the file attributes, and they were fine. Changing them did not change the icon.
Windows stores many icons in the Shell32.dll file (%SystemRoot%\system32\SHELL32.dll). It was there in Windows 11.
Microsoft updated many of the icons in Windows 11, so I checked Shell32.dll in Windows 10 to see what the icon used to look like. It showed a black clock icon in the same position in the file.
Googling for “windows black clock overlay icon” was a success. I found an article from 2003 by Microsoft’s Raymond Chen that referenced the black clock:
A black clock. This really baffles people. This means that the file has been archived to tape and will take a very long time to access.
Although we're not archiving to tape anymore, the icon is used when the FILE_ATTRIBUTE_OFFLINE flag is set, which is why it is used for files synchronized using a cloud service. The "file" we see is a pointer to the file since the actual file is offline and it will take a little longer to open than it would if stored locally.
Another Raymond Chen article mentioned only the first 15 custom overlays on the custom overlay list are used. My DropBox icons start at 24th on the list, so I get the file drawer icon, indicating it will take longer to access the file. His article also mentioned they stopped putting the offline overlay on individual files and used it only on the folder. It looks like someone changed their mind when it came to cloud synchronization.
The list is stored in the registry at HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellIconOverlayIdentifiers.
More Information
These are the articles I found when I searched for "black clock overlay icon":
What are those little overlay icons? – The Old New Thing (microsoft.com)
What are those little overlay icons: Windows 7 edition – The Old New Thing (microsoft.com)
file attributes – Black-clock icon overlay? – Super User
The thread that piqued my curiosity:
Office documents appear with an orange/yellow box in front of – Microsoft Community