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OSX Installation Guide

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Quick install guide

We recommend SpiderOak as a privacy-conscious cloud backup provider. The first 2Gb are free.

We have a Getting Started guide so you can be up and running with Bitcoin quickly and safely.

There are more tutorials on our YouTube channel MultiBitOrg.

How to install on OS X (Mac)

The MultiBit installer is slightly different from a standard OS X installer in that it doesn't rely on a single drag and drop into the Applications directory. However, once the installer has completed the resulting package in Applications can be dragged to the launch bar as usual.

Requires OS X Lion or higher

For security reasons MultiBit requires OS X 10.7.3 (Lion) or higher. You can get a free OS X upgrade from the Apple app store.

Bitcoin software requires a secure environment and OS X Lion (released in 2011) is quite old now. We urge you to upgrade to keep your system up to date.


Occasionally people encounter problems getting MultiBit set up on their OS X machine. Here are some common solutions to known problems.

I don't have much system memory

MultiBit uses the Java Virtual Machine (JVM) to manage its memory. This means that over time you will see memory use increase as various activities take place. Synchronizing with the block chain is a memory-intensive process and during the initial sync or a Repair Wallet operation you will notice an increase. By default MultiBit will not consume more than the lesser of one quarter of your system memory or 1Gb. For example, on a 2Gb system (2009 mid-range machine) MultiBit will start having memory constraints at around 500Mb.

This default is sufficient to allow for smooth and responsive operations on most systems. However, MultiBit can continue to work with only 256Mb allocated to it although performance tends to reduce.

If you want to change the memory allocated to MultiBit you will need to do the following:

  1. After installation, locate MultiBit in the Finder (in Applications)
  2. Right click and select "Show Package Contents"
  3. Open Contents/vmoptions.txt in a text editor
  4. Edit the line # -Xmx512m to remove the # and following space
  5. Change the value to something else, e.g. -Xmx1024m is 1Gb
  6. Save the changes and use the shortcut as normal to start MultiBit

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