Hello, I've used Boxcryptor and Microsoft's OneDrive for several years without seeing this message from OneDrive on my Windows 10 (latest OS & updates, and latest OneDrive and Boxcryptor) on my new computer. The new computer uses an SSD drive rather than a traditional hard drive, so that might be what's causing this message to appear now (race condition that didn't show up on the slower drive technology).
Details: I installed Boxcryptor and it automatically set up a OneDrive folder in the X virtual drive which appears to be linked to the folder OneDrive sets up. So, anything copied into X:\OneDrive appears in the C:\users\xxx\OneDrive folder. That is what I expect. I have a scheduled job that does the following:
xcopy C:\backup_xxx X:\OneDrive /s /e /m /y /D
As the files are copied into this folder, OneDrive notices files appearing in C:\users\xxx\OneDrive and begins the sync process. Sometimes this works without generating the subject message. But, every so often, I see the subject message when right clicking on the OneDrive tray icon. Clicking the message shows that the file can't be synced because the file is in use (open) in another process, and once closed OneDrive claims it will sync it.
I believe OneDrive does in fact sync it properly because I do see it when I look at my OneDrive cloud account. Because of this, I'm not too concerned about correct operation. What bugs me is I keep getting this message from OneDrive, and it accumulates as different files may be in this state as time goes on. OneDrive never clears these messages after the file has been synced. Only a reset of OneDrive clears the message.
I'm reporting this to here in the hopes that because your expertise might be more likely to understand what's going on than Microsoft. You know, two independent products and each developer points fingers that the other. I will report this to Microsoft, too, but I'd like your take on this issue.