When the hash value of a file does not match its known good hash, it generally indicates that the file has been altered. Alterations could be due to an update or patch, malicious activity, or file corruption. However, given that this is a security investigation context, the observation raises the suspicion of potential tampering or infection by malware which is often why integrity checks using hashing are performed. Other options such as transmission errors or hashing algorithm inconsistencies are less likely in this scenario since the focus is on system files that are not typically transmitted over the network and the hashing algorithm is assumed to be a constant.