The GSTN on 12.07.2024 has issued an Clarification through twitter post, regarding 𝐁𝟐𝐂 𝐭𝐚𝐛𝐥𝐞 𝐨𝐟 𝐓𝐚𝐛𝐥𝐞 -𝟏𝟐 (𝐇𝐒𝐍 ) 𝐨𝐟 𝐆𝐒𝐓𝐑-𝟏. 

This reads as under:

Table 12B is not mandatory — It can be left blank or filled with any value.

Issue:

However, some taxpayers with only B2C sales face issues if Table 12A (B2B HSN summary) is left blank. This is occurring in cases where they have any entry in Table 8.

Solution:

If there are no B2B supplies, you still need to have one entry in Table 12A. For this, you can enter any HSN code and any UQC in Table 12A, and fill all other fields with “0” in order to proceed.

This way, the system will not show any error. The system is expected to be upgraded shortly to further simplify this step for filing GSTR-1 when there is only B2C supply.

Source: GSTN Tech Twitter Post