Question:  When I start the TekExpress application on my oscilloscope, I get a "Scope status returned as: PASS:UNCAL - The instrument is not fit for duty and the results might be invalid." error message.  I just had my scope calibrated so does this mean that it is now un-calibrated?

The error message you are experiencing is an bug in firmware version (V6.4.5).  This version had bug where it reports UNCAL.  This is fixed the later versions of the firmware.  I would recommend upgrading to a later version.  At the time of this FAQ publication, V6.7.4 was the current version.  This or later versions can be downloaded from Tek.com through the "Downloads, Manuals and Documentation" section.  /node/7106.  Enter in your instrument model number, select "Software" as download type.  In the results screen, filter by "Firmware".