If process "trustd" is using 100% (or any large amount) of CPU...
This is usually caused by a damaged system keychain. Delete /Library/Keychains/system.keychain. Restart computer.
Note 1: This causes saved passwords, certificates, etc to be lost, so use with caution. Note 2: Optionally, open keychain first and make a note of any important passwords. Note 3: Only applies to system keychain, which should not contain your passwords.
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