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Oracle Troubleshooting

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ORA-01102: cannot mount database in exclusive mode

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Symptom:

When opening or mounting the database, the following error is generated:

ORA-01102: cannot mount database in EXCLUSIVE mode.

Cause:

I have only come across this error when using Oracle Parallel Server (OPS). Here, this error indicates that another instance has already been mounted in exclusive or parallel mode.

Possibly Remedies:

• Mount the database in parallel mode.
• Shutdown all other instances before mounting the database in exclusive mode.
• Try stopping and then restarting the service 'OracleService<SID>'.

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This page represents one page of many pages of notes I made whilst working with Oracle 7 through to 10i. I now no longer work with Oracle databases, but hope that these notes will continue to be of benefit to others.