My inventory and sales reports dont show my last months numbers. What could be the issue ?

Glad to have you here, @michael132.

There are several reasons you're unable to view your data on inventory and sales reports. I recommend checking the following to check the root cause of this:

• The date ranges of the reports do not match.
• The accounting bases of the reports do not match. (cash or accrual)
• Sales items point to incorrect sales accounts.
• The P&L report includes transactions that do not use items (e.g., the Expense Tab on a bill or a journal entry).

Once done verifying and you can't still access the data, I recommend opening your QuickBooks Online account using a private browser. Cache tends to hold onto information that causes issues in the web pages.

• Google Chrome: press Ctrl + Shift + N  
• Safari: press Command + Shift + N

Once signed, try to access the reports. If you're able to see the data, I recommend clearing the browser's cache. Doing so can improve the program's performance.

However, if private browsing doesn't work, I recommend using different browsers. They will provide you the best and most secure experience with QuickBooks. For more details, see this article: System Requirements For QBO.

Additionally, I've included an article that will help you learn more about how inventory tracking can affect your Balance Sheet and Profit & Loss reports: Impacts of Inventory Tracking on Financial Reports.

You may also want to consider memorizing the reports in QuickBooks Online. This helps save the current customized settings for easy access in the future.

I'm always here to help. For other QuickBooks concerns, keep us updated to fix them.