Start-up disk almost full?

[watercool]

Last week I installed an SSD and kept my standard HDD. I installed Yosemite and used the SSD for everything apart from music, a load of images and such.

Now I keep getting the 'startup disk almost full' message. I'm assuming this is my SSD....how can I monitor whats on this drive and know what there is to move (and how to move!) things onto my HDD.

Thanks!

 

[GGJstudios]

This should help: Freeing up drive space in Mac OS X

There are a few things you can try, some of which may or may not apply:

• Begin by restarting your computer as a first step. This sometimes resolves issues.
• For Time Machine users on notebooks running Lion or later, space may being consumed by Time Machine local snapshots, which can be disabled by entering the following command in Terminal: sudo tmutil disablelocal.
  About Time Machine's "local snapshots" on portable Macs​
• Check to see if some of the space is being used by your sleepimage file.
• Search with Finder to see if the space is being consumed by a very large file or several large files. Adjust the 50GB in the illustration to whatever size you deem appropriate.
  
• Use OmniDiskSweeper, JDisk Report, Disk Inventory X, DaisyDisk or GrandPerspective to see how space is being used on your drive. Some of these apps may show more detail than others, so try several.
• Check your drive with Disk Utility: Using Disk Utility to verify or repair disks
• Try re-indexing your drive: Spotlight: How to re-index folders or volumes

Here are a few resolutions found by others with the same question:

• Encrypted drive
• Time Machine backup files and needed disk repair
• App filling log file
• App or file was 89GB
• Drive needed to be re-indexed
• Time Machine backup file
• Large app cache file
• Garageband files and video podcasts
• Oversized email being duplicated
• Another email issue
• 18.45EB of movies shown
• Duplicate movies in iPhoto app