Error 900 when attempting to add music library
Error 900 occurs when there is not enough storage space on the Server service to buffer the data. The Server service runs on Windows computers and supports file and printer sharing. The solution is to increase the stack size of the Server service on the computer that your music library is stored on. If your music is stored on a USB drive and is connected to your computer through an external USB hub, try bypassing the hub and connect the drive directly to the computer if the steps in the link below do not work.
Be aware that this involves editing the Windows registry and can be harmful to your computer if not done correctly.
If you are comfortable making edits to your Windows registry to fix this, you can find the steps to resolve this on the Microsoft support site linked below. While the article mentions that these steps are for Windows XP, the same steps apply for Windows Vista, and Windows 7 & 10 as well. If you are not comfortable making these changes, or the steps provided here did not help resolve the issue, please reach out to our Customer Care team for further assistance.
Reboot your computer after making these changes to your Windows registry.