If this were April 1, I might give directions for building a gremlin trap.
Errors can accumulate in a computer. They can originate by sheer chance, or a bit can be twiddled as a cosmic ray zips through a chip. A cache file can be corrupted. A software hack installed on the computer may change code in OS X with unfortunate consequences.
When unexpected things happen, the first thing to try is a Restart. That clears the computer’s memory and freshly reloads the operating system, applications and data files. It’s one of the things Jim and I often suggest when we receive a Support ticket describing abnormal behavior by DEVONthink. And that suggestion was the answer for many cases.
Generally when I recommend trying a Restart, I recommend that first, DEVONthink’s cache be cleared as well (Application Name > Empty Cache, in the menubar).
I follow a routine of preventive maintenance of my Mac and its operating system. Once in a while I run Disk Utility’s Verify Disk procedure. Yes, my MacBook Pro Retina with a 500 GB SSD has developed disk errors several times, and my checks have allowed repair before serious problems developed. If you run this routine every few weeks and never find an error, your time has not been wasted.
Every two or three weeks, and immediately if I see flaky behavior, I run an OS X maintenance utility. I use C0cktail; the free OnyX application is similar. I run a suite of procedures such as permissions check, cache cleaning, etc. These procedures are available in Apple’s Terminal application, but the utility apps make them user-friendly.
I try to avoid installing utilities that change features or functions of OS X, especially those that actually modify code in OS X. Some of those utilities promise time-saving and convenience, and I sacrifice those advantages by not using them. Perhaps I’m a nut about this. But my operating system tends to stay clean and efficient, and I rarely see problems on my Macs. I periodically run Tools > Verify & Repair on my DEVONthink Pro Office databases, and haven’t seen an error for a very long time.
If flaky behavior persists after Restart, Disk Utility checks and running an OS X maintenance utility, a hack installed on the computer may be the source of problems. This can be checked by running DEVONthink in a Guest account.
Once in a while DEVONthink, a complex application that has many procedures, develops a bug, or a call made to OS X hits a bug in OS X. Send in a ticket to Support if you find a bug in OS X. We want to know, so bugs can be fixed.