Open the configuration file in Notepad++ (not regular Notepad — encoding errors matter). Look for entries like:
[DATABASE]
DataSource=C:\TecDoc\Data\catalog.dat
DataFormat=SQLITE
LicenseKey=XXXX-XXXX
Or in XML:
<connectionStrings>
<add name="TecDocDB" connectionString="Data Source=D:\TecData\master.tcd" />
</connectionStrings>
Correct the path:
Pro tip: Copy the exact path from File Explorer and paste it into the config file to avoid typos.
Even if your configuration file is perfect, Windows may block TECDOC from reading it. This is the #1 cause of the error on Windows 10/11. Open the configuration file in Notepad++ (not regular
Once you have resolved the issue, implement these safeguards:
Right-click the configuration file → Open with → Notepad (do not use Word or rich text editors). Correct the path:
If you have tried all the above and still see "TECDOC loading data failed – check the configuration file install," prepare the following for support:
TecAlliance support can often provide a hotfix or a patched configuration file tailored to your setup. " prepare the following for support:
Use Windows Search to find *.cfg or *.xml inside the TECDOC installation folder. Typical paths:
C:\TECDOC\Config\
C:\Program Files (x86)\TecAlliance\TECDOC\
C:\Users\Public\Documents\TecAlliance\