I'm trying out some extensions, google bookmark cloud and tree but they only work till next restart.
I have the impression that the first time they inherit the connection settings and they have connection to the internet, and after restart they don't have these setting and lack a connection to the internet.
Each time I start up, I have to give chrome my username and password before the first page can load. Shouldn't that be kept somewhere by chrome? And passed to the extensions?

What is the version of Chrome that you are running?
Go to the Wrench and select About Google Chrome

What is the version of Operating System that you are running?

not related but I had a bad experience with dev Chrome 5 minutes ago;
shut down Chrome and all extensions were missing and the preferences file was changed

I have version 4.0.266.0 on win XP SP3.
This is going on for days now, since the extensions are available.

try adding " --enable-local-storage" to Chrome shortcut and see whether it helps

nope, that doesn't work.

can you provide the link to the extensions so that I can test at my end ?

google bookmark cloud:
https://chrome.google.com/extensions...gfbcbccnjokdaj
google bookmark tree:
https://chrome.google.com/extensions...emeonegeofmfcf

I'm sure it will work for you. For me the problem resides in the connection through my company's proxy.
I can change the settings for Chrome itself, but the settings aren't passed to the extensions, I guess.

When I deactivate the extension and reactivate it, it works. Something is done while activating that isn't done at startup.

have you tried uninstalling and reinstalling

Yes I did a lot. Each time it works till next restart.