WaaSMedicAgent is responsible for repairing Windows Update when it breaks. Unfortunately, the Medic Agent itself can cause problems by having high RAM, high CPU, and high disk usage. Luckily, the WaaS MedicAgent can be disabled completely.
No software is perfect — things go wrong, and files break, including Windows Updates (especially Windows Updates). Windows as a Service Medic Agent (WaaSMedicAgent) was introduced in Windows 10 to “Enable remediation and protection of Windows Update components.” In other words, it fixes problems with Windows Update that might prevent your PC from updating.
This process is supposed to run when Windows encounters a problem with an update. Unfortunately, the Medic Agent itself has been known to cause problems. In some cases, it bogs down PCs for hours by maxing out CPUs, causing extremely high RAM usage, and causing high disk usage.