Hi @Amit Nemade
It may be worth having a read of my blog on model categories to understand how they function throughout an asset or CI's lifecycle: https://www.servicenow.com/community/in-other-news/assets-configuration-items-and-model-categories-u...
In short, the Model Category field on an asset is mandatory on creation but should normally be populated after the Model is chosen as it is then filtered (e.g. in the baseline if you set the Model to "Dell Inc. Alienware M14x" then the Model Category option is reduced to just "Computer"). Once saved neither field can be modified because the field-level Access Controls for writing are set to the role "Nobody".
From your original post it is not clear what steps you have taken - were the monitors created via import set or some automation that bypassed setting the Model Category? And are you talking about monitor Assets or their related Configuration Items? I presume you have Assets with empty Model and/or Model Category?
If so then the Update Job @Brad Bowman mentions above will help but bear in mind a couple of things:
- When setting the Condition field, if you choose a field of type = Reference you cannot actually look the record up (so you won't be able to distinguish between two models with the same display name, but after clicking Continue you can preview the number of records that would be impacted). Oddly the "Fields and values" field does support a lookup for Reference fields.
- System Update Jobs requires the admin role.
More importantly, I recommend reviewing the process for creating the assets in the first place and fix this issue so that it does not happen in future.
