I have had two reports in the last week of the Outlook2CRM toolbar disappearing in Outlook. The toolbar was there before, but then out of the blue, it was no longer showing up. An uninstall or reinstall did not fix the problem. For both cases, it turned out to be an update from the users anti-virus program that disabled any Outlook addins, including Outlook2CRM.

If this happens to you, all that is needed is to remove Outlook2CRM from Outlook's "disabled addins" list and all is well again. No need to reinstall or anything. The FAQ has an entry titled "Why can't I see the Outlook2CRM toolbar in Outlook" which includes a section "Check Outlook's Disabled Items list". It has the following text:

In Outlook, go to the "Help" menu, then "About". In the bottom right corner of the About dialog there is a "Disabled Addins" button. Click this button. If "Outlook2CRM for Sage SalesLogix", "Outlook2CRM", or "OutlookAddinShim.dll" appear on this list, select it and click the "Enable" button.

Once you remove Outlook2CRM from the disabled items list it will immediately show up again.