I have a MacBook Pro running Mavericks. I installed DropBox and it worked for a couple of days. Now for the last week or so, (since the last Mavericks update I think), whenever I launch Dropbox I get the message "Couldn't start Dropbox." Here's a picture: http://imgur.com/k7PVSbe Here's the text that is in the link in the error message: http://imgur.com/xu1QhbH I contacted DropBox support but they did not solve my problem. Here's what they said: It looks like you may have some files with permissions settings that block Dropbox. This often happens with users who may have migrated old data and settings from another Mac to their current computer. Operating system permissions prevent files from being viewed or edited by unauthorized logins. Permissions can be set any number of ways and can be restored manually through a fairly simple process. Please note that it is very important to follow these steps specifically as failure to do so may result in other issues: 1) Make sure the Dropbox desktop application is running 2) Click on the Dropbox icon in your menu bar and then click on the gear in the Notifications panel 3) Select 'Preferences' 4) Click on the 'Account' tab 5) Hold down the 'Option' key 6) Click on the 'Fix Permissions' button (make sure you're still holding down the 'Option' key. This will allow Dropbox access to your home folder, Dropbox folder, and any required settings. ** However, on Step 3 - I cannot select "Preferences", as it is grayed out. I informed them of this days ago but they did not get back to me. Any ideas?