I'm just testing C5 on a new host, I just have default 5.6.0.1 installed using a supplied theme. I had entered a couple of comments in guestbook and when I edit the page and toggle any of the block settings, such as approval, require Captcha etc when i save any previous entries are now missing. I don;t have access to Cpanel (long story) and so they have installed C5 for me. Previously there were some issue of permissions to allow add-on installation. Also today i could not download the recent 5.6.0.2 update, the dashboard page times out to some non-descript looking system page with error 1460 timeout. I'm wondering if it might be more permissions related issues? I can't check the permissions as they all show 000. I don;t know how to check the database without cPanel.

Edit. I am now seeing similar error on downloading 5.6.0.2 as previous with add ons. Warning: copy(F:\WebHosting\xxxxxxx.com.au/updates/concrete5.6.0.2/concrete/blocks/autonav/icon.png) [function.copy]: failed to open stream: No such file or directory in F:\WebHosting\xxxxxxx.com.au\concrete\core\helpers\file.php on line 71
So I guess updates has wrong permissions too. Can a permissions issue cause the Guest Book issue?

Edit: I downloaded the database and I can see the previous entries are in there but not showing on the actual page. I'm not expert at reading the export from this but I think maybe there are 3 guestbook databases, the btguestbook looks like this…

INSERT INTO btguestbook VALUES(34,0,'Tell us what you think','M jS, Y',1,1,0,'')
,(73,1,'Tell us what you think','M jS, Y',1,1,0,'')
,(74,0,'Tell us what you think','M jS, Y',1,0,0,'');

and btguestbookentries has all the entries, but they corresponds to 34, 73, or 74. The number of entries associated with either 34, 73 or 74 seem to relate directly to how many entries were in there before I edited the block.

So is the problem that on each edit of the block, a new table has been created. Again I'm no expert but this would seem to explain what I'm seeing here.