Macbook Pro all of a sudden very slow.

Question

My Macbook Pro has all of a sudden become very slow. The rainbow wheel shows up about every minute, and battery life has reduced a lot. I lost about 10% of my battery life within 10 minutes. It freezes all of the time. I recently upgraded to mountain lion about a month ago and everything has been fine since about 2 days ago. Any ideas on what it could be?

Answer 1

First, back up all data immediately, as your boot drive might be failing.
There are a few other possible causes of generalized slow performance that you can rule out easily.
If you have many image or video files on the Desktop with preview icons, move them to another folder.
If applicable, uncheck all boxes in the iCloud preference pane.
Disconnect all non-essential wired peripherals and remove aftermarket expansion cards, if any.
Otherwise, take the steps below when you notice the slowdown.
Step 1
Launch the Activity Monitor 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 Activity Monitor in the icon grid.
Select the CPU tab of the Activity Monitor window.
Select All Processes from the menu in the toolbar, if not already selected.
Click the heading of the % CPU column in the process table to sort the entries by CPU usage. You may have to click it twice to get the highest value at the top. What is it, and what is the process? Also post the values for % User, % System, and % Idle at the bottom of the window.
Select the System Memory tab. What values are shown in the bottom part of the window for Page outs and Swap used?
Next, select the Disk Activity tab. Post the approximate values shown for Reads in/sec and Writes out/sec (not Reads in and Writes out.)
Step 2
If you have more than one user account, you must be logged in as an administrator to carry out this step.
Launch the Console application in the same way you launched Activity Monitor. Make sure the title of the Console window is All Messages. If it isn't, select All Messages from the SYSTEM LOG QUERIES menu on the left.
Select the 50 or so most recent entries in the log. Copy them to the Clipboard (command-C). Paste into a reply to this message (command-V). You're looking for entries at the end of the log, not at the beginning.
When posting a log extract, be selective. Don't post more than is requested.
Please do not indiscriminately dump thousands of lines from the log into this discussion.
Important: Some personal information, such as your name, may appear in the log. Anonymize before posting. That should be easy to do if your extract is not too long.