I have had
Colornote since it came out, never an issue.
I have "Auto" BK's set up & do an occasional "manual" BK with my pass to my external SD card (FYI: online sync is also available in settings)
The data for ColorNote is located on my external SD cared device: data/colornote/backup
So look for that location you should see numbered files named #-Auto (for auto BKs) & #-MANUAL with extensions of: .dat & .idx
You can also BK your notes online-sync in the settings menu to Gmail , fakebook & Colornote via AES email.
Check to see if it's still on your device go to: Settings - Applications - Manage Applications - ColorNote - (Move to Device (optional))
Q : Where is backed up notes data at sdcard?
A : /data/colornote on sdcard
Q : I had to reinstall color notes notepad and there is an automatic backed up notes data that was stored but it requires a password and I hadn't set one up in the past. How do I retrieve that information?
A : Try default password '0000' (numbers)
Q: I forgot my master password, how can I change it?
A: Menu -> Settings -> Master Password -> Menu Button-> Clear Password. You will lose current locked notes when you clear password!
Check the info here & it has the link to email them for support
Colornote
It's a great program & never had any issues, so hope that may help you