Here is a great tutorial on how to fix the WordPress Plugin, WPtouch so that it can work with W3 Total Cache plugin.

After installing and enabling W3 Total Cache:

1. Go to the Page Cache settings under the Performance tab

-Scroll down to the Rejected user agents box and paste the WPtouch default user agents (found below). Save changes

2. Go to the Minify settings page under the Performance tab

-Scroll down to the Rejected user agents box and enter the WPtouch default user agents. Save changes

3. Go to the CDN settings page under the Performance tab

-Scroll down to the Rejected user agents box and again enter the WPtouch default user agents. Save Changes

4. Finally, go to the General Settings page under the Performance tab and click empty all caches.

Your blog should now be configured correctly to work with WPtouch and W3 Total Cache correctly.

Add one user agent per line.

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