I need some advice. I have two identical Mac Minis, both Mid 2010 with Intel Core 2 Duo, 2.4 GHz, 8 GB DDR @1067. The one I rarely use (home) is running 10.7 and is fine. The other one (work) is running 10.12 and has slowed considerably. I use it for general business stuff: email, word processing, excel, calendar, internet, etc. Here is what I have tried: I cleared out some space on the hard drive so that I have 20% clear, but that showed very little improvement. I rebooted (Command-R) and went through the disk utility protocols. I reinstalled 10.12.6 over the weekend. It took several hours to complete, and that has helped some. I am still getting a beachball intermittently, and it lags a bit sometimes when I type. I am not sure whether the machine is re-indexing after the upgrade, which could cause some delays. The EtreCheck log has improved. The only concerns now are: System Launch Agents: (What does this mean?) [failed] com.apple.NetworkDiagnostics.plist [loaded] com.apple.bluetooth.PacketLogger.plist - Executable not found! [loaded] com.openssh.ssh-agent.plist [Click for support] System Launch Daemons: (What does this mean?) [failed] com.apple.NetworkDiagnostics.plist [loaded] com.apple.airplaydiagnostics.[redacted].mac.plist - Executable not found! [loaded] com.apple.driver.ethcheck.plist - Invalid signature! [loaded] com.apple.driver.ethcheckthunderbolt.plist - Invalid signature! [loaded] com.apple.emlog.plist - No signature! [loaded] com.apple.gkreport.plist - No signature! [failed] com.apple.mobile.keybagd.plist - Executable not found! [loaded] com.apple.postfix.newaliases.plist - No signature! [loaded] org.apache.httpd.plist - No signature! [loaded] org.net-snmp.snmpd.plist - No signature! Is there anything I need to do to address those items? I have read where the installation of an SSD improves performance. Should I give that a try? Do I clone my current HD onto the SSD before I install it, or do I install the new drive, then boot with Command-R, and then use Time Machine to restore my apps? Any help or advice would be appreciated.