Alfred is compatible with OSX 10.6 (Snow Leopard) and 10.7 (Lion) Intel Macs, however 10.7 is recommended to take advantage of all of the current and future features.
In addition, Alfred is built on top of the OS X metadata which is maintained when Spotlight is enabled (by default) on these versions of OS X. For Alfred to be able to serve you fully, you should not turn off Spotlight indexing.
If you encounter issues with Spotlight continuously reindexing, this tip may help you out.
OS X 10.5 Leopard - Intel and PPC versions
On OS X 10.5 (Leopard) Intel or PPC and wish you could get some Alfred goodness too? We provide an unsupported PPC version of version 0.9, which is the last build tested for 10.5.
Leopard Intel
media.alfredapp.com/alfred_0.9_final_126.dmg
Leopard PPC
media.alfredapp.com/alfred_0.9_final_126_PPC.zip
Note: disable auto update checking in the PPC version as it checks for the Intel version.
Note: on 10.5 and just bought the Powerpack? Drop us an email at info@alfredapp if you're having problems activating the license.
You may have found this answer by using one of these keywords: