The provider is not compatible with the version of Oracle client

Question

I'm trying to use the Oracle ODP.NET 11g (11.1.0.6.20) Instant Client on my ASP.net project as a Data Provider but when I run the aspx page I get a "The provider is not compatible with the version of Oracle client" error message. Any help would be appreciated.

I've referenced the Data Provider in Visual Studio 2005 and the code behind looks like this:

using Oracle.DataAccess.Client;
..

OracleConnection oOracleConn = new OracleConnection();
oOracleConn.ConnectionString =
    "Data Source=MyOracleServerName;" +
    "Integrated Security=SSPI";
oOracleConn.Open();

//Do Something

oOracleConn.Close();

The error for the page looks like this:

Exception Details: Oracle.DataAccess.Client.OracleException: The provider is not compatible with the version of Oracle client

Source Error: 
Line 21: 
Line 22: 
Line 23:             OracleConnection oOracleConn = new OracleConnection();
Line 24:             oOracleConn.ConnectionString =
Line 25:                 "Data Source=MyOracleServerName;" +

[OracleException (0x80004005): The provider is not compatible with the version of Oracle client]
   Oracle.DataAccess.Client.OracleInit.Initialize() +494
   Oracle.DataAccess.Client.OracleConnection..cctor() +483

Stack Trace: 
[TypeInitializationException: The type initializer for 'Oracle.DataAccess.Client.OracleConnection' threw an exception.]
   Oracle.DataAccess.Client.OracleConnection..ctor() +0
   Boeing.IVX.Web.RoyTesting.Page_Load(Object sender, EventArgs e) in C:\Documents and Settings\CE218C\Desktop\IVX.Net\Web\IVX\RoyTesting.aspx.cs:23
   System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +15
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +33
   System.Web.UI.Control.OnLoad(EventArgs e) +99
   System.Web.UI.Control.LoadRecursive() +47
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1436

user_59198 · Answer

I've been looking into this problem further, and you simply need to grab all the appropriate DLL's from the same downloaded version of ODP.Net and put them in the same folder as your Exe file, because ODP.Net is fussy about not mixing version numbers.

I've explained how to do this here: http://splinter.com.au/using-the-new-odpnet-to-access-oracle-from-c Here's the gist of it though:

Download ODP.Net
Unzip the file
Unzip all the JAR's in it
Grab these dll's that were just unzipped:
- oci.dll (renamed from 'oci.dll.dbl')
- Oracle.DataAccess.dll
- oraociicus11.dll
- OraOps11w.dll
- orannzsbb11.dll
- oraocci11.dll
- ociw32.dll (renamed from 'ociw32.dll.dbl')
Put all the DLLs in the same folder as your C# Executable

user_74908 · Answer

I only installed the Oracle Data Provider for .NET 2.0 (11.1.0.6.20) and I did not install the Oracle Instant Client (11.1.0.6.0).

I just installed it and the error disappeared!

user_114105 · Answer

This can be caused by running a 64bit .NET runtime against a 32bit Oracle client. This can happen if your server you are running the app on it 64 bit. It will run the .NET app with the 64bit runtime. You can set the CPU flag on your project in VS to run in the 32bit runtime.

user_266414 · Answer

install ODP.Net on the target machine and it should solve the issue... copying the dll's does not look a good idea...

Peter_Meyer_1875 · Answer

It would seem to me that though you have ODP with the Oracle Istant Client, the ODP may be trying to use the actual Oracle Client instead. Do you have a standard Oracle client installed on the machine as well? I recall Oracle being quite picky about when it came to multiple clients on the same machine.

Admin · Answer

I had the exact same problem. I deleted (and forgot that I had deleted) oraociei11.dll after compiling the application. And it was giving this error while trying to execute. So when it cant find the dll that oraociei11.dll, it shows this error. There may be other cases when it gives this error, but this seems to be one of them.

user_3926461 · Answer

This issue could by happen while using unmanaged oracle reference if you have more than one oracle client , or sometimes if you reference different version
There is two way to solve it :

First and fast solution is to remove unmanaged reference and use the managed one from NuGet see this before to go with this option Differences between the ODP.NET Managed Driver and Unmanaged Driver
Second solution is to fix project unmanaged target version like the below :

First Check oracle project reference version (from project references/(dependencies > assemblies ) > Oracle.DataAccess right click > properties):

Then check oracle GAC version

got to gac from run (Win+R) "%windir%\Microsoft.NET\assembly"
Check the platform that matches with you project platform
to check you target platform (right click on your project > properties)
From gac folder search to Oracle.DataAccess
Right Click on Oracle.DataAccess > properties > details and check version
if you notice the versions are different this is an the issue and to fix it we need to redirect assembly version (in startup project go to config file and add the below section )

like this

oldVersion : should be cover your project version newVersion : GAC version publicKeyToken : From GAC

DCookie_8670 · Answer

Does the IIS/IWAM user have permissions on the Oracle directory? Can you connect to this data source using another app, such as Excel or Access?

user_4278837 · Answer

I faced a similar issue and the root cause was that GAC had 2 oracle.dataaccess versions i.e. v4.0_4.112.2.0 and v4.0_4.112.4.0 . My application was referring to v4.0_4.112.2.0 , so when I removed v4.0_4.112.4.0 from GAC, it worked fine.

GAC path : C:\Windows\Microsoft.NET\assembly\GAC_64\Oracle.DataAccess

Before :

After :

To remove a version, one can simply delete the corresponding folder from GAC.

The provider is not compatible with the version of Oracle client

27 Answers