Summary:

By default, the Acronis Files Connect (formerly ExtremeZ-IP) service logs on as the local SYSTEM account. This relies on the default ACE that grants the SYSTEM account Full Control over all NTFS volumes. Permission issues can arise if the local System account is missing or does not have full control on your NFTS file system. 

As an example, if a Mac client performs an operation that needs to calculate free disk space but the user does not have the necessary rights, Acronis Files Connect will perform this calculation using the SYSTEM account. While Acronis Files Connect requires the system account to have full control at the root of the drive (drive letter) as well as the root of the directory being shared out, it is also recommended to have the default SYSTEM=Full Control ACE inherit unbroken down the file hierarchy.

Description:

You can use icacls to restore the necessary permissions

Example:

Open a command window: Start > Run > cmd [return]
Change directory to the drive letter root: E: [return]
Run the following: icacls *.* /T /C /Q /grant System:F

Any errors reported should be investigated and resolved.