You are asked to download the Client anew for each session.
Do not use Chrome Incognito mode or Firefox Private Browsing mode. You will always experience this problem when trying to use LogMeIn in Incognito or Private Browsing mode.
If you are not using a private mode and still experience this problem, you must set your browser to remember cookies across sessions.
If you do not want to allow all cookies, you must at least create a cookie exception for logmein.com in your browser’s Privacy settings. For your convenience, we've gathered links to cookie configuration instructions:
When starting a remote session, Firefox may display a “Launch Application” dialog. Please simply enable “Remember my choice for logmein links”, and click OK, without browsing for an application. The entry selected by default should simply work (“LogMeIn Client Application” or “Launch LogMeIn Client”)
If Clear history when Firefox closes is enabled under Privacy settings, click Settings to the right of this option, uncheck Cookies, and click OK. This option overrides cookie exceptions, so cookies must be excluded from this.