How To Fix MC266 - Could not create pool & in ABAP Dictionary

MC266 - Overview

• Message type: E = Error

• Message class: MC - Aggregate: views, matchcodes, lock objects

• Message number: 266

• Message text: Could not create pool & in ABAP Dictionary

What causes this issue?

The physical matchcode IDs (update types A, S, and P) for a matchcode
object are stored in a pool. This pool is automatically stored in the
ABAP Dictionary when the matchcode object is generated. The name of the
pool is formed from the prefix M_ and the name of the matchcode object.
In this case, the creation of the pool was not successful - for example,
because another pool already exists with the name chosen as standard.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Try to get further information about the error using the activation
logs.

Error message extract from SAP system. Copyright SAP SE.

MC266 - Details

• The SAP error message MC266, which states "Could not create pool & in ABAP Dictionary," typically occurs when there is an issue with the creation of a database pool in the ABAP Dictionary. This can happen for several reasons, and understanding the cause is essential for finding a solution.
  Causes of Error MC266
  
  
  Database Issues: The underlying database may have issues, such as being down, misconfigured, or having insufficient resources (like disk space).
  
  
  Authorization Problems: The user may not have the necessary authorizations to create database objects in the ABAP Dictionary.
  
  
  Naming Conflicts: There may be a naming conflict with existing database objects, such as tables or views.
  
  
  Technical Settings: Incorrect technical settings for the database table or pool can lead to this error.
  
  
  Transport Issues: If the object is being transported from one system to another, there may be issues with the transport request.
  
  
  Database Connection: Problems with the database connection settings in the SAP system