How to fix the running total is missing value or replace the blank with previous month value

Kwaritnon , Make sure you are using a date table in the visual and measure formula. Or try window function if needed

 

examples

 

Cumm Sales = CALCULATE(SUM(Sales[Sales Amount]),filter(all('Date'),'Date'[date] <=max('Date'[date])))

Cumm Sales = CALCULATE(SUM(Sales[Sales Amount]),filter(allselected(date),date[date] <=max(date[Date])))

 

year behind

Cumm Sales = CALCULATE(SUM(Sales[Sales Amount]),filter(allselected(date),date[date] <=maxx(date,dateadd(date[date]),-1,year)))

 

Why Time Intelligence Fails - Powerbi 5 Savior Steps for TI :https://youtu.be/OBf0rjpp5Hw
https://amitchandak.medium.com/power-bi-5-key-points-to-make-time-intelligence-successful-bd52912a5bd4

 

Power BI Window function Rolling, Cumulative/Running Total, WTD, MTD, QTD, YTD, FYTD: https://youtu.be/nxc_IWl-tTc

 

Running Total/ Cumulative: https://www.youtube.com/watch?v=h2wsO332LUo&list=PLPaNVDMhUXGaaqV92SBD5X2hk3TMNlHhb&index=41