Failed to store Mail in configured archive
Question / Problem
This error occures while trying to store emails with the Exchange Server Toolbox:
Failed to store Mail in configured archive store: Failed to create mail signature for mail [...] in archive store because an exception occurred, Exception occurred while hashing & signing data with SHA256 algorithm: The object already exists.
Answer / Solution
This error is caused by missing access rights to a key file. This is located in the folder C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys. You can either change the permissions on the entire folder or check which file needs the permissions.
To find out which file this is, you can use window's own "Procmon". This shows all file accesses. Open the program and set the filter "Path contains C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys". Then check which file the "Jam.EST.Archive.Writer.Service.exe" process tries to accessand allow access to this file.