Houston County Schools in Alabama had to delay their school year’s opening due to a malware attack and the ongoing recovery. It has not been disclosed what type of malware attack they were hit with, but sounds like a ransomware attack based upon the details given. There are 4,000 computer systems that were affected and all of them have to be reimaged before they can get the network back up and running. This has lost the district 7 days of school, which the state has decided not to force them to make up.
Source: https://www.bleepingcomputer.com/news/security/malware-attack-delays-alabama-districts-school-year-twice/