Okay, it seems you are using Finder to search for your files. There are many other methods available to locate files. The first thing I would l'd try is restarting in Safe Mode. If you use a wireless keyboard, please connect the charging cable to the back of the iMac (this will make it a wired keyboard) while doing the Safe Mode restart. When you hold down the Shift key, continue holding it down for up to 10 minutes until the computer starts in Safe Mode. After the Safe Mode restart, please restart normally and test.
If you live in an area where power can go out then it may be wise to invest in a battery backup as. computers do NOT like sudden power losses and can fail as a result.
If you want to try another method of finding your files use Spotlight which is the magnifying glass symbol in the upper right of the display. The keyboard shortcut for launching Spotlight is Command + Spacebar. You can use spotlight to easily find files. For example if you are looking for a specific recipe such as "boiling an egg" (yes I'm being over simplistic) simply type boiling an egg in Spotlight and it will find the file(s) and also tell you where they are located. Spotlight can also be used for launching apps, simply type in the name of the app and it will launch. I prefer this method over using the Dock, navigating to the Apps folder or using other methods. For example if you want to load iMovie just type iMovie and it will launch. You can learn more about Spotlight in Search for anything with Spotlight on Mac - Apple Support
Another method is there is a third party app called FindAnyFile which is great too, easy to use and personally I prefer it over Finder.
