Hello Elfak,
If you are having issues with permissions, even though you state the issue is with the Numbers application, I'd like to suggest you try these steps:
1. Verify Disk Permissions using the Disk Utility application and checking the Macintosh HD.
2. Verify the Numbers application permissions from the Get Info windows.
You could also try to create a new document in your current user, or try to create a document in the Numbers application at iCloud.com.
Here are some resources that explain these in more detail:
Resolve startup issues and perform disk maintenance with Disk Utility and fsck
http://support.apple.com/kb/TS1417
Try Disk Utility
- Open the Applications folder in Finder. Double-click the Utilities subfolder to open it. Double-click Disk Utility.
- Click the First Aid tab.
- Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
- Select Macintosh HD
- Click Repair Disk Permissions.
Troubleshooting permissions issues in Mac OS X
How to View and Change Permissions in the Finder's Info Window
The Mac OS X Finder can be used to inspect and modify permissions settings for some files and folders. You can only change permissions for files and folders of which you are the owner. This can aid in troubleshooting permissions-related issues. To view and change permissions in the Info window, follow these steps:
- Select a file or folder in the Finder.
- From the File menu, choose Get Info.
- Click on the discloure triangle in the Sharing & Permissions section
- Using the pop-up menus, change permissions settings to Read & Write
- Optional: If you are changing permissions for a folder and you want the changes to apply to enclosed folders as well, click Apply. Apply only appears when you show info for folders.
iCloud: Use iCloud.com
https://support.apple.com/kb/PH2610?locale=en_US
Regards,