After installing Equitrac Office / Express 5.7 the folder C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys keeps growing in size.
This issue can be caused by the Equitrac DCS service not having the required components installed. This will cause DCS service to continuously restart, causing the C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys to grow in size.
On the Windows server, in the Add roles and services wizard, install the ASP.net 4.5 feature from the .NET Framework 4.5 section, for Windows Server 2012 R2. For newer OS versions, the .NET Framework version will be newer.
If the DCS hotfix is installed, .NET 4.6.1 must also be installed.
The above will stop adding new files.
Due to the nature of how Windows handles DCS machine keys in the folder, in order to remove them, assistance from Microsoft will be required to do so safely. Removing files may result in unexpected behavior. Open a ticket with Microsoft technical support.