This is a time-saving procedure, but it's very advanced. If you don't feel comfortable with it, don't attempt it. Ask for a simpler procedure that will take much longer.
1. If you don't already have a current backup, back up all data. There are ways to back up a computer that isn't fully functional. Ask if you need guidance. Don't skip this step.
2. Disconnect all external storage devices.
3. To simplify these instructions, I'll assume that there is only one installation of OS X on the startup drive. If there's more than one, the procedure may need to be modified.
4. Start up in Recovery mode. The OS X Utilities screen will appear.
5. This step is only necessary if you use FileVault 2. If you don't know what FileVault is, you're not using it. Go to the next step. Otherwise, launch Disk Utility, then select the icon of the FileVault volume ("Macintosh HD," unless you gave it a different name.) It will be nested below another icon with the same name. Click the Unlock button in the toolbar and enter your login password when prompted. Then quit Disk Utility to be returned to the main screen.
6. Select Get Help Online. Safari will launch. While in Recovery, you'll have no access to your bookmarks, but you won't need them. Load this web page.
7. Triple-click anywhere in the line below to select it:
ls -d /V*/*/S*/*/Extensions/Eltima*
Copy the selected text to the Clipboard by pressing the key combination command-C.
8. Quit Safari. From the menu bar, select
Utilities ▹ Terminal
The Terminal application will launch. Paste into the Terminal window by pressing the key combination command-V.
A new line should appear below what you entered, ending in something like "EltimaSync.kext". If that happens, enter this command in the same way as the last one:
mv $_ $_/../../../../tmp/
Wait for a new line ending in a dollar sign ($) to appear. Quit Terminal to be returned to the main screen.
9. Select
▹ Restart
from the menu bar.
