Try this:
1) Shut down Chrome by pressing Command+Q while Chrome is the active application. Check the Dock for the Chrome icon. If present, right-click it and click Quit if this menu item is available.
2) delete the following 2 files in /Users/USERNAME/Library/Application Support/Google/Chrome/Default/Local Storage/:
chrome-extension_edacconmaakjimmfgnblocblbcdcpbko_0.localstorage
chrome-extension_edacconmaakjimmfgnblocblbcdcpbko_0.localstorage-journal
3) Restart Chrome and test the Previous Session autosave.
If that doesn't work, you can reinstall SB without losing your data by following the instructions here:
How to Back Up and Restore Session Buddy Data (Advanced):
You can also just back up the data through SB and import it after reinstalling. This is an easier process, but I would also save a copy of the local user data folder just to be safe.
Hans