Message type: E = Error
Message class:  BM - Development class BZME - units of measure 
Message number: 021
Message text: You have deleted & unit(s)
The units of measure that you selected will be deleted.
The units of measure were flagged as deleted within the maintenance
transaction and are no longer offered for maintenance.
To delete the units from the database, save your entries.
Error message extract from SAP system. Copyright SAP SE.
The SAP error message BM021 ("You have deleted & unit(s)") typically occurs in the context of inventory management or material management when a user attempts to perform an action on a material or batch that has been deleted or is no longer available in the system. This can happen in various scenarios, such as during stock transfers, inventory counts, or when trying to access a material that has been marked for deletion.
Cause:
Deletion of Material/Batches: The material or batch you are trying to access has been marked for deletion in the system.
Data Inconsistency: There may be inconsistencies in the database, such as orphaned records or incomplete transactions.
User Permissions: The user may not have the necessary permissions to access certain materials or batches that have been deleted.
System Configuration: Certain configurations in the system may lead to the deletion of units under specific conditions.
Solution:
Check Material Status: Verify the status of the material or Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
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