why incessant spinning beach ball and WAIT! WAIT! on 10.10.4

Try restarting the computer and see if that helps. If it does not please post an EtreCheck report of the computer and we can look for obvious causes. You can get EtreCheck by clicking http://www.etresoft.com/etrecheck

When you see a beachball cursor or the slowness is especially bad, note the exact time: hour, minute, second.

These instructions must be carried out as an administrator. If you have only one user account, you are the administrator.

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 and start typing the name.

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.

Each message in the log begins with the date and time when it was entered. Scroll back to the time you noted above.

Select the messages entered from then until the end of the episode, or until they start to repeat, whichever comes first.

Copy the messages 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 it useless for 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.

When you post the log extract, you might see an error message on the web page: "You have included content in your post that is not permitted," or "The message contains invalid characters." That's a bug in the forum software. Please post the text on Pastebin, then post a link here to the page you created.

I too was having this issue. I checked the console and found I was getting disk errors now on my Time Machine backup.

7/1/15 12:38:53.966 PM Console[616]: Failed to connect (_consoleX) outlet from (NSApplication) to (ConsoleX): missing setter or instance variable

7/1/15 12:39:36.000 PM kernel[0]: disk2s2: I/O error.

7/1/15 12:39:36.000 PM kernel[0]: /SourceCache/AppleFSCompression_kexts/AppleFSCompression-68.30.1/Common/ChunkCo mpression.cpp:209: /Volumes/TimeMachine/Backups.backupdb/Beast/2015-06-29-164248/Macintosh HD/Applications/iMovie.app/Contents/Frameworks/Flexo.framework/Versions/A/Resou rces/es.lproj/FFConsumerTransportControlsFullscreen.nib: VNOP_GETXATTR(5766,32u): errno 5

7/1/15 12:39:36.198 PM com.apple.mtmd[45]: handler get failed. (status=-1/errno=5/Input/output error/token=0/flags=0/fd=-1/path=unknown)

7/1/15 12:39:36.216 PM com.apple.xpc.launchd[1]: (com.apple.imfoundation.IMRemoteURLConnectionAgent) The _DirtyJetsamMemoryLimit key is not available on this platform.

I turned off the external USB3 drive I back up too and the issue has gone away. I have to much work to get done to test if turning on the drive brings the issue back, but I will to that later today and report back.

OK it appears my TimeMachine disk has died, I plugged it back in and it will not mount. Since I disconnected it I have not had the spinning beach ball.