I'll break up the problems I have encountered into separate pieces. The first one: I could not get a UNO with a multiplexer to run a standard switchboard on FSX. I followed up on Pizman82's advice to start RUN. (Message #27505). I restarted everything and followed the advice: it worked. In the following days and weeks, it did not work anymore. See the copy of the .mcc file (see below). Is there an error in the programming? When running it, the RUN........ indicator on the taskbar moves, as if everything is correct. If so what else could be the problem?
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<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<MobiflightConnector>
<outputs />
<inputs>
<config guid="2efc7af4-acd1-489b-85da-e869945f4eb3">
<active>true</active>
<description>MAGNETO_RIGHT</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="RIGHT" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="66024" param="1" />
<onRelease type="EventIdInputAction" eventId="66024" param="0" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
<config guid="c23c662f-8ae8-493d-a1ac-a36145d89340">
<active>true</active>
<description>MAGNETO_LEFT</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="LEFT" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="66025" param="1" />
<onRelease type="EventIdInputAction" eventId="66025" param="0" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
<config guid="2c5f75da-c369-4cee-a232-fc97ac5a9bb5">
<active>true</active>
<description>MAGNETOS_BOTH</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="BOTH" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="66026" param="1" />
<onRelease type="EventIdInputAction" eventId="66026" param="0" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
<config guid="4dceb768-5e61-4022-abae-6ccc0b436022">
<active>true</active>
<description>START</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="START" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="66725" param="1" />
<onRelease type="EventIdInputAction" eventId="66725" param="0" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
<config guid="a56eaecc-f9ee-473d-a3bf-8bb7fb689898">
<active>true</active>
<description>MASTER_ALT</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="MASTER" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="66374" param="1" />
<onRelease type="EventIdInputAction" eventId="66374" param="0" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
<config guid="25c241e9-df83-443c-8e5b-1f38512c7d0a">
<active>true</active>
<description>MASTER_BATTERY</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="MASTER" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="66374" param="1" />
<onRelease type="EventIdInputAction" eventId="66241" param="0" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
<config guid="f5f1ac9d-ee23-4fb1-a600-bcfeeef2f42e">
<active>true</active>
<description>FUEL_PUMP</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="FUEL" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="65957" param="1" />
<onRelease type="EventIdInputAction" eventId="65956" param="1" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
<config guid="d18a9288-a6e7-4e23-9013-5c9fc1880553">
<active>true</active>
<description>BEACON_LIGHT</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="BEACON" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="66239" param="1" />
<onRelease type="EventIdInputAction" eventId="66239" param="0" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
<config guid="954588d0-7595-4826-aa92-9bf7d9aaf40e">
<active>true</active>
<description>LANDING_LIGHT</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="LANDING" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="65751" param="1" />
<onRelease type="EventIdInputAction" eventId="66060" param="0" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
<config guid="8a9b5391-4823-4f06-a9d1-ca465f15644f">
<active>true</active>
<description>TAXI_LIGHT</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="TAXI" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="66240" param="1" />
<onRelease type="EventIdInputAction" eventId="66240" param="0" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
<config guid="a2f15dad-a9a1-40d4-bf67-def6fab23025">
<active>true</active>
<description>NAVI_LIGHTS</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="NAV" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="66379" param="1" />
<onRelease type="EventIdInputAction" eventId="66379" param="0" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
<config guid="ec2876f0-675b-447e-af57-22c46e6fecf6">
<active>true</active>
<description>STROBE</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="STROBE" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="65560" param="1" />
<onRelease type="EventIdInputAction" eventId="65560" param="0" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
<config guid="7b41469f-6de5-494b-86c5-afd369c2a3b1">
<active>true</active>
<description>PITOT_HEAT</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="PITOT HEAT" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="65858" param="1" />
<onRelease type="EventIdInputAction" eventId="65858" param="0" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
<config guid="09fcc8a2-f8c9-49d4-9fef-393eecb5a4a9">
<active>true</active>
<description>AVIONICS</description>
<settings msdata:InstanceType="MobiFlight.InputConfigItem, MFConnector, Version=9.7.0.0, Culture=neutral, PublicKeyToken=null" serial="MobiFlight Uno/ SN-58FFDFFFDFFFFFFFFF" name="AVIONICS" type="Button" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<button>
<onPress type="EventIdInputAction" eventId="66701" param="1" />
<onRelease type="EventIdInputAction" eventId="66701" param="0" />
</button>
<preconditions />
<configrefs />
</settings>
</config>
</inputs>
</MobiflightConnector>