iMac Safari jumps once and stops...

Open a Finder window. From the Finder menu bar click Go > Go to Folder

Type or copy paste the following

~/Library/Caches/com.apple.Safari/Cache.db

Click Go then move the Cache.db file to the Trash.

Quit and relaunch Safari to test.

If that doesn't help, see if you can launch Safari from your Applications folder.

Try shutting down and restarting - Have had the can't get in can't get out loop happen. If you cannot disconnect from the internet and can't shut down you may have to just kill the power.

Launch the Console application in any of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad. Click Utilities, then Console in the icon grid.

The title of the Console window should be All Messages. If it isn't, select

SYSTEM LOG QUERIES ▹ All Messages

from the log list on the left. If you don't see that list, select

View ▹ Show Log List

from the menu bar at the top of the screen.Click the Clear Display icon in the toolbar. Then try the action that you're having trouble with again. Select any messages that appear in the Console window. Copy them to the Clipboard by pressing the key combination command-C. Paste into a reply to this message by pressing command-V.

The log contains a vast amount of information, almost all of which is irrelevant to solving any particular problem. When posting a log extract, be selective. A few dozen lines are almost always more than enough.

Please don't indiscriminately dump thousands of lines from the log into this discussion.

Please don't post screenshots of log messages—post the text.

Some private information, such as your name, may appear in the log. Anonymize before posting.

You probably ran a defective third-party "utility" such as "CleanMyMac" or "MacCleanse" that purports to "clean up" "junk" files. What it really does is to corrupt the operating system and many applications.

The first thing you need to do is remove that software according to the developer's instructions. Never install it, or anything like it, again. Then see below.

If you don't already have a current backup, back up all data. There are ways to back up a computer that isn't fully functional. Ask if you need guidance. You can skip this step if you don't care about the data that hasn't been backed up.

Reinstall the OS.* Your data should be unaffected unless something goes wrong. If the system was upgraded from an older version of OS X, you may need the Apple ID and password you used.

If you use FileVault 2, then before running the Installer you must launch Disk Utility and select the icon of the FileVault startup volume ("Macintosh HD," unless you gave it a different name.) It will be nested below another icon with the same name. Click the Unlock button in the toolbar and enter your login password when prompted. Then quit Disk Utility to be returned to the main Recovery screen.

If you installed the Java runtime distributed by Apple and still need it, you'll have to reinstall it. The same goes for Xcode. All other data will be preserved.

*The linked support article refers to OS X 10.9 ("Mavericks"), but the procedure is the same for OS X 10.7 ("Lion") and later.

"CleanMyMac" is a scam. I've found it being distributed through the same channels as the "Genieo" trojan.

The developer's instructions don't completely remove it. Follow those instructions, then do as below.

Back up all data.

Triple-click anywhere in the line below on this page to select it:

/Library/LaunchDaemons/com.macpaw.CleanMyMac2.Agent.plist

Right-click or control-click the highlighted line and select

Services ▹ Reveal in Finder (or just Reveal)

from the contextual menu.* A folder should open with an item selected. Move the selected item to the Trash. You may be prompted for your administrator login password. Repeat with this line:

/Library/PrivilegedHelperTools/com.macpaw.CleanMyMac2.Agent

Restart the computer and empty the Trash. Never again install "CleanMyMac" or anything like it.

*If you don't see the contextual menu item, copy the selected text to the Clipboard by pressing the key combination command-C. In the Finder, select

Go ▹ Go to Folder...

from the menu bar and paste into the box that opens by pressing command-V. You won't see what you pasted because a line break is included. Press return.

If those files don't exist, then you don't need to remove them.