If you downgrade from Chrome or Chrome Beta , you may get:

When starting Chrome, the program generates a message

'Your profile cannot be used because it is from newer version of Google Chrome.

Some features may be unavailable. please specify a different profile directory or use a newer version ofChrome.'

Here is the fix / at least one of them:

(Example)

c:\Users\HP\AppData\Local\Google\Chrome\User Data\Default\Web Data

I deleted the Web Data folder.

Closed Windows Explorere, Opened Chrome

*** If you have a MAC , this may apply


I ran into the same problem and just fixed it. What other users suggested here works - the trick is to find the right Library folder. Depending on how your Mac was setup, you may have more than one Library folders - one under your Macintosh HD and another under Users folder. I found my Google (profile) folder under Users folder. The following is the steps to fix the problem:
1. Click to open your Users folder, then open the folder for your current user, say "Tom", open "Tom" folder, then open the Library folder.
2. Open Application Supper folder;
3. Find Google folder (if you want to sure to get the right one, click to open it, there should be Chrome sub-folder in it);
4. Delete this Google folder and all folders inside it.
5. Restart Chrome;
6. You can enjoy Chrome again without that annoying message!
Note: If you sync your google settings before, you can re-sync and get your bookmarks back.