As of recent releases, Google Chrome's settings are now locked to a given PC with a generated signature on the settings files. This affects the portable version as you move between PCs either via removable drive or via cloud drive. It also affects the local version if you move your profile as part of restoring a backup from one PC to another or upgrading to a new PC and copying your profile over.
If you don't change any standard settings or use extensions, you are unlikely to notice or be affected by this. Bookmarks, cookies, passwords, and other data are unaffected. This affects search engine selection, homepage, new tab settings, as well as most extensions and settings. Signing into Google Chrome should restore your settings if you were signed in last time, but it will be required that you do so and re-download your settings and extensions on every PC. If you're not signed in to Google, you'll simply lose your settings. Google Chrome is designed to not give you any notice of this except a small message at the top of the Options window if you happen to open it.
We're looking into handling this using some of the same bits we use to handle passwords in Google Chrome. Google Chrome's passwords are normally similarly locked to a single PC. We have a custom bit of code in our launchers that can convert them to/from this encrypted format as well as (optionally, but recommended) encrypt them as you move between PCs. We may be able to adapt this to handle the new Secure Preferences signatures.
Browsers based on the same engine like Chromium, Iron, and Opera are not affected by this issue. Self-contained browsers that do not hook into the OS like Firefox and SeaMonkey have no such issues. Illegal packages of Google Chrome made portable from other sites are all affected by this issue.
Please keep unrelated commentary to a minimum as this thread is primarily about investigating and solving this bug. Comments about this also affecting your install or that it is important to fix are unnecessary. Thank you for understanding.
Some additional background is available in the original thread: http://portableapps.com/node/42591
Workaround to maintain extensions, settings, and session
For those users who don't wish to sign in, a possible suggested workaround is to sign in to Google to restore all settings and extensions and to use an extension such as Session Buddy to maintain your session state as you move PCs. Note that PortableApps.com has no evaluated this extension. Thanks, XiL.