A good place to start looking is in SpiderOak ONE's deleted items bin. To protect against accidental or malicious deletion, SpiderOak's copies of files you've deleted on your computer are moved here. For your protection, SpiderOak never empties this folder automatically, so over time it can become quite large.
To check your deleted items bin, open the Manage tab in the SpiderOak application on your computer. In the Devices column on the left, you will see a list of all your devices, and each has a Deleted Items bin. Select one. Once selected, you can delete its entire contents with the Empty button.
You can also browse or delete individual items in the same way you would any other item from your SpiderOak account. Find a file or folder you wish to delete. Select it and the Remove button will become active. Press the Remove button to delete the selected item.
Each device in your SpiderOak account has its own deleted items bin, so check them all. As a security measure, you can only delete files and folders associated with the computer you are seated at. If you select a file or folder associated with another computer, you will notice that the Remove button does not activate. This is a common cause of difficulty.
To make removal of files easier, make sure the Full Paths toggle button is enabled. It's found near the top of the Manage tab. Once you've done that, you will see while browsing the deleted items bins of your devices that there's probably only one or two top level folders, with everything inside it. If you wish to empty the deleted items bin and delete everything, you can select that top level folder and remove it.
You might also check to see if you have a very large number of historical versions saved. Usually these deduplicate, but some file structures don't deduplicate effectively and your historical versions might be taking up a lot of space. Microsoft Office and Outlook files are well known file types that don't deduplicate well and commonly overrun storage space. To delete a historical version, see Deleting Historical Versions. Although it is an advanced technique, you can also purge all your historical versions at once by using the command line.
Many users have unnecessary "junk" files selected for backup. For example: temporary internet files, cookies, "Recent" menu, and so on. These are files that would serve no purpose to restore, so there's no point in backing them up. They change often and accumulate a lot of historical versions. Our recommendation is to back up only your documents and other user files, not application or system data. For more information on this, see What Data Should I Back Up?
Once you get the immediate problem taken care of, we suggest you periodically check the storage bar at the bottom of the application. It shows how much space you have in your account and how much of it you are using. This will let you know ahead of time if you are in danger of running out of space.