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Windows: 'TNS: Protocol Adapter Not Loadable'Error When Trying To Connect From Another Oracle Home TNS-12557 (Doc ID 556895.1)

Last updated on DECEMBER 01, 2016

Applies to:

Oracle Net Services - Version to [Release 10.2 to 12.1]
Microsoft Windows x64 (64-bit)
***Checked for relevance on 3-JUNE-2015***


A Windows machine has two ore more Oracle homes installed. Connections from the usual home are working, but when trying to connect from the other Oracle home (by changing the environment) it fails with error: “TNS-12557: TNS: Protocol Adapter not Loadable”.

A client trace shows these errors:

[05-MAR-2008 21:31:51:441] sntrf: LoadLibrary on E:\Ora92\bin\orantcp10.dll returned error(126)
[05-MAR-2008 21:31:51:441] nserror: entry
[05-MAR-2008 21:31:51:441] nserror: nsres: id=0, op=77, ns=12557, ns2=12560; nt[0]=527, nt[1]=0, nt[2]=0; ora[0]=0, ora[1]=0, ora[2]=0
[05-MAR-2008 21:31:51:441] nsc2addr: error exit
[05-MAR-2008 21:31:51:441] nsclose: entry
[05-MAR-2008 21:31:51:441] nsclose: normal exit
[05-MAR-2008 21:31:51:441] nladget: entry
[05-MAR-2008 21:31:51:441] nladget: exit
[05-MAR-2008 21:31:51:441] nsmfr: entry
[05-MAR-2008 21:31:51:441] nsmfr: 212 bytes at 0xd84570
[05-MAR-2008 21:31:51:441] nsmfr: normal exit
[05-MAR-2008 21:31:51:441] nladtrm: entry
[05-MAR-2008 21:31:51:441] nladtrm: exit
[05-MAR-2008 21:31:51:441] nscall: error exit
[05-MAR-2008 21:31:51:441] nioqper:  error from nscall
[05-MAR-2008 21:31:51:441] nioqper:    ns main err code: 12557
[05-MAR-2008 21:31:51:441] nioqper:    ns (2)  err code: 12560
[05-MAR-2008 21:31:51:441] nioqper:    nt main err code: 527
[05-MAR-2008 21:31:51:441] nioqper:    nt (2)  err code: 0
[05-MAR-2008 21:31:51:441] nioqper:    nt OS   err code: 0
[05-MAR-2008 21:31:51:441] niomapnserror: entry
[05-MAR-2008 21:31:51:441] niqme: entry
[05-MAR-2008 21:31:51:441] niqme: reporting NS-12557 error as ORA-12557
[05-MAR-2008 21:31:51:441] niqme: exit
[05-MAR-2008 21:31:51:441] niomapnserror: exit
[05-MAR-2008 21:31:51:441] niotns: Couldn't connect, returning 12557


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