First meet part
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Missed a multi-language web interface;
When the user can write down his/her fax number, create a promotion for your online fax service

;
Got the message, "user name is at least 6 characters", same with password. Can you write next to the input fields a "min 6 chars" or something similar?
At step3, it should be "Order" or "Finalize order", etc. instead of "Next >>".
When i finished the order confirm reading, it said an "upto" (should be up to). Maybe a javascript counter would be nice here.
New account signup: It's really not clear for the user what the first step means. You must explain for them in details if you leave it this form.
What is "Number of Users"? I mean is that the number of servers/clients or the user number of clients at the same time or?
I can log in at the same time from client/server machine, is that good?
I've checked my notebook's status from the notebook: offline ... I logged in again and i got the Connect button (so user must log out and in to apply UA Server installation?).
The Machines' list page should refresh itself if i'm logged in (fe. 60-360 seconds).
I suggest to put a help icon at every page at signing up which lead to help pages or can switch on/off a CSS property help pane (solved with display or visibility tags, etc.).
Registered for 30 days
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After logged in i found that the top menus aren't helping me at all.
License Detail: Valid To is "-". It's a 30 days trial, isn't?
The first installation must be the UA server, why? It's 1.5MB, not a too small package.
Server install
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Can't modify destination path!
+documents for firewall settings (~maybe the user won't use CPF)
/UaConnect.exe out 53 udp/
Alphanumeric names only

(if i right-click the server's tray icon and choose Connection Info, you put a "+" between the names where i used spaces).
/UAHost.exe out 195.92.252.119:443/
Access code is max 8 characters and at least 6 (it's not a should and it's a weak point, no freedom /consider to change this/).
Client install
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The what (client)? No, really, more documents, please

.
I've logged in and choosed my notebook's Connect button, got the "Download the viewer version of UserAnywhere" page. Fun, viewer, not client, i'm so confused.
I've clicked the Download and had downloaded the UAViewer.Exe file.
Double-clicked: out 53 udp; 195.92.252.120:443 (UAviewer with ComodoUA.exe parent).
A comodo window asked the password... What if i have forgot which computer is the one i'm working with? You should leave an option to show computer name.
Connection is established... if the computer isn't in energy safe mode?
Client
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We don't know any infos about what the maximum resolutions and refresh Hzs are.
The client user is no longer able to recognise which computer he's useing unless he knows that he can see the remote computer name at top-right: which is maybe not important if the name is something like pc12345-pc. I suggest the same, write down the server's name somewhere.
You should create a "stay alive" button with on/off switches.
I'd suggest plugin usages what the user can use just in case. Fe.
Admin plugin 1: sysdm.cpl, devmgmt.msc, cmd.exe, etc.
User plugin 1: outlook.exe, iexplore.exe, etc. (~or default mail client/browser, etc.)
File Transfer
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If i miss-click the File transfer window, it'll be in the background. Can you improve it's button to call it back to top (of any window) if i click it?
It'll be nice to see the drive names (i suggest a different color for system volumes).
Connection
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I'll be disconnected if the another machine will go into stand-by mode.
Everything is closed at client part but the server part remains active (xy is remotely connected window). It was absolutely unclear what to do to get the online status back (documents, please). Steps:
1. re-download the ua server installer;
2. run it;
3. choose update;
4. re-do everything...
Is the clipboard secured?
Edit: fixed some grammar things ^^