When you try to load the Trados Studio add-in the following error message appears in the Add-ins > Translation window:

Please install SDL Trados Studio software to use "SDL Trados Studio" addin.
If it is already installed, provide the installation directory on addin's settings.xml file.
 

Until a permanent solution is implemented, the workaround is to add the path of the Trados Studio installation directory in the Passolo settings.xml file which can be found in one of the below folders:

• for Passolo 2015: C:\Program Files (x86)\SDL\SDL Passolo\SDL Passolo 2015\System\DnTradosStudio 
• for Passolo 2016: C:\Program Files (x86)\SDL\SDL Passolo\SDL Passolo 2016\System\DnTradosStudio 
• for Passolo 2018: C:\Program Files (x86)\SDL\SDL Passolo\SDL Passolo 2018\System\DnTradosStudio 
• for Passolo 2022: C:\Program Files (x86)\Trados\Passolo\Passolo 2022\System\DnTradosStudio

If you are using the Passolo Translator Edition, the file can be found in the corresponding folder. In case of Passolo Translator 2022, this would be C:\Program Files (x86)\Trados\Passolo\Passolo Translator 2022\System\DnTradosStudio.

The content of the settings.xml file should be as below: 
 

• For Trados Studio 2024 translation memory (TM) integration:

<?xml version="1.0" encoding="utf-8" ?> 
<TradosStudioSettings> 
<!-- If Passolo does not find the Trados Studio installation path you can enter it here --> 
<InstallLocation>C:\Program Files (x86)\Trados\Trados Studio\Studio18</InstallLocation> 
</TradosStudioSettings>

• For Trados Studio 2022 TM integration:

<?xml version="1.0" encoding="utf-8" ?> 
<TradosStudioSettings> 
<!-- If Passolo does not find the Trados Studio installation path you can enter it here --> 
<InstallLocation>C:\Program Files (x86)\Trados\Trados Studio\Studio17</InstallLocation> 
</TradosStudioSettings>

• For Trados Studio 2021 TM integration:

<?xml version="1.0" encoding="utf-8" ?> 
<TradosStudioSettings> 
<!-- If Passolo does not find the Trados Studio installation path you can enter it here --> 
<InstallLocation>C:\Program Files (x86)\SDL\SDL Trados Studio\Studio16</InstallLocation> 
</TradosStudioSettings>

• For Trados Studio 2019 TM integration:

<?xml version="1.0" encoding="utf-8" ?> 
<TradosStudioSettings> 
<!-- If Passolo does not find the Trados Studio installation path you can enter it here --> 
<InstallLocation>C:\Program Files (x86)\SDL\SDL Trados Studio\Studio15</InstallLocation> 
</TradosStudioSettings>

• For Trados Studio 2017 TM integration:

<?xml version="1.0" encoding="utf-8" ?> 
<TradosStudioSettings> 
<!-- If Passolo does not find the Trados Studio installation path you can enter it here --> 
<InstallLocation>C:\Program Files (x86)\SDL\SDL Trados Studio\Studio5</InstallLocation> 
</TradosStudioSettings>

• For Trados Studio 2015 TM integration:

<?xml version="1.0" encoding="utf-8" ?> 
<TradosStudioSettings> 
<!-- If Passolo does not find the Trados Studio installation path you can enter it here --> 
<InstallLocation>C:\Program Files (x86)\SDL\SDL Trados Studio\Studio4</InstallLocation> 
</TradosStudioSettings>

After the content of the settings.xml  is updated, re-load the Trados Studio add-in from Passolo (Tools tab -> Add-ins -> Translation, select Trados Studio add-in from the list, right-click -> Load).
 

Development is aware of the issue and a new CU will be released for Passolo to integrate automatically Trados Studio 2015 or Trados Studio 2017 translation memories.