Where can i find Oracle.DataAccess.dll?


Can anyone help me how can i find Oracle.dataAccess.all for Oracle Instant Client I try to connect my application with database, but i got this error:

Could not load file or assembly 'Oracle.Web, Version=, Culture=neutral' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from RESULT: 0x80131040)

Can someone help me with this?

asked on Stack Overflow Jun 24, 2020 by norganorga

1 Answer


By default the Oracle Instant Client does not include the Oracle Data Provider for .NET, i.e. Oracle.DataAccess.dll. You must download and install from ODAC Runtime Downloads

Note, the provider is very sensitive regarding the version. ODP.NET version (which means does not work with Oracle Client

They have to match exactly!

Usually it does not make any sense to install an Oracle Instant Client and then add the ODP.NET. Install the needed ODAC from above, the Oracle Instant Client is always included in any Oracle Client installation package.

answered on Stack Overflow Jun 24, 2020 by Wernfried Domscheit

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