Lion no longer installs all the printer drivers out of the box, I guess to cut down on unnecessary downloading from the Mac App Store. On 10.7.1 it wouldn’t let me add a printer with the error:
The software for this printer is currently unavailable. Please contact the printer’s manufacturer for the latest software.
However by running Software Update (from the Apple menu bar) after connecting the printer, it successfully downloaded the correct drivers. The Add Printer option then automatically installs the printer once selected.
Update, thanks to Rob in the comments for his suggestion that seems to be helping a lot of people:
If running Apple’s Software Update doesn’t fix it for you, open Preferences->Print & Scan and then hit ctrl-click (or right mouse) over the list of printers and select “Reset Printing System…”. That will uninstall all your printers but then I was able to add the Officejet by clicking the “+” button and the error went away.
Update 04/08/2011: last.fm have updated their client, either use the Check for updates.. in the app or download it.
Still no scrobbling but the release notes show they’ve fixed it for Lion:
1.5.4.28012 (mac) (04/08/11)
—————————-
* Plugin fix for iTunes 10.5
* 64bit version of the plugin for iTunes on Lion
Original:
Sadly the last.fm client doesn’t autostart under Lion when you run iTunes; and there’s yet to be an official update. In fact the entire client has been rather neglected, seeing its last update in October 2010.
If like me, you’ve lost a bunch of scrobbles because you’ve forgotten to open it, you can add last.fm to your login items so it’ll automatically open when your Mac starts.
Open System Preferences then > Users & Groups; select your username and toggle to the Login Items page. Click the + and select the last.fm app to add to the list.

If like myself, you have the last.fm not show in the dock (and only the menu bar), select the Hidden checkbox.
Unfortunately there’s no iPhone / iPad scrobbling support on Lion yet, and I’m not sure how iOS 5 WiFi sync will be able to handle it..
When installing or updating Xcode you need to close iTunes for it to complete. If you’ve closed iTunes but still get this message:

Open Activity Monitor and quit iTunes Helper. The installation will now finish.
This mainly seems to happen on beta versions of iTunes. The helper app runs to detect iOS devices being connected so it can auto-open iTunes.

Hey call me! (and give my laptop back)
In Mac OS X Lion you can now add a short message to the login screen. It’s a long shot but adding contact details might increase the chances of a lost machine being recovered by 0.5%.
To update the message go to System Preferences > Security & Privacy > General where you can choose Show a message when the screen is locked.

Don’t forgot to use your own number, although I am happy for any lost laptops to be sent to me.
Due to some cookie restriction in Lion the latest stable or beta version of Adium cannot connect to Facebook chat.
Luckily they just re-enabled their nightly builds which fix the issue.
Download the latest nightly from: http://nightly.adium.im/
Make sure you get the 1.4.3 nightly currently: http://nightly.adium.im/?repo_branch=adium-1.4-default
As the 1.5 builds are unstable.
Update: Adium have now released a beta fixing this issue: http://beta.adium.im/. Betas are usually more stable than nightlies so use this!
After upgrading to Lion I found it disabled a few of the system fonts. This made lots of websites not display as intended and warnings about Missing Fonts in Pages (which had the benefit of artificially inflating my book’s page count bringing it nearer completion).
Turns out Lion can disable certain fonts in certain circumstances; I did a clean install of Lion on a different drive when running the Install Mac OS X Lion app.
You can re-enable the fonts like this:
- Open Font Book, it’s stored in your Applications folder. You’ve got Lion now so you could be fancy and use Launchpad.
- Find a font that has been disabled — in my case Verdana was the key one. Right click the font and select Enable ‘font name’ Family:

- Repeat this for any other fonts that have been disabled.
You can automatically activate fonts added in the future by ticking Automatic font activation from the Font Book Preferences menu:

Looks like in Safari 5.1 in Lion disk images (.dmg) are no longer classed as “Safe” files after the whole Mac Defender cat and mouse malware saga.
The enabled by default “Open ‘safe’ files after downloading” preference of Safari automatically opens certain types of files as a convenience aid.
Safari 5.0 on Snow Leopard:

Safari 5.1 on Lion:

I found this quite useful, but I guess it’s just another move closer to an ‘App Store’ only world..