unable to display inbox messages

in MS outlook express my inbox folder showing the message that unable to open the folder while others folder displaying ok.

Are there any error messages that pop up? If so, what do they say?

outlook express is pretty outdated, no longer supported by MS. It might be time to move on to outlook.com. Maybe your inbox problem will resolve its problem with the migration.

See this: http://windows.microsoft.com/en-us/windows/outlook-express#tabs=windows-8

If you have backup of Outlook Express data, then use guide below, if not, then you may take a look at additional helpful articles/topics about getting rid of .dbx corruption

https://social.msdn.microsoft.com/F...ile-of-outlook-express?forum=messengerconnect
https://social.technet.microsoft.co...ook-express-recovery-tool?forum=olmdiscussion
https://www.openfiletool.com/dbxopen.html DBX Open File Tool – this solution provided for complicated .dbx corruptions, and only for them

If you carefully follow these instructions, you may be able to recover them.
1. First CLOSE Outlook Express.
2. Hopefully you haven’t emptied your recycle bin yet. DON’T EMPTY IT.
3. Click to open your Recycle Bin and do check it. Do you see any files that end in .bak, like drafts.bak, sent.bak, and especially inbox.bak. If you do, it’s recoverable. But DON’T right-click and choose restore YET. (If you don’t see the files there, they may be in another folder, which you’ll get to later. At any case, they’ll have the .bak extension.)
4. If you’re not already viewing details, choose VIEW from the top menu, and click on DETAILS. This is so you can see the original file location.
5. The original file location could look something like this:
 C:\Documents and Settings\Default\Local Settings\Application Data\Identities\some string\inbox.bak
 (Default could be some other name, some string is the string that you were given, which is different for different users.)
6. You’re going to have to find that original folder, but you might have to reveal hidden files and folders to do so. Local Settings are usually hidden.
 Click START, Choose CONTROL PANEL, and Click FOLDER OPTIONS (for Windows 7, you’ll have to click on APPEARANCE AND PERSONALIZATION link first before you can click on FOLDER OPTIONS.) Then click VIEW and look in the ADVANCED SETTINGS Window for SHOW HIDDEN FILES AND FOLDERS. Click that radio button if it isn’t already chosen, then click the OK button.
7. Now you’re ready. Find that folder, and look for an inbox.dbx. That is your current INBOX.
8. Right-click inbox.dbx and rename it inbox2.dbx, just in case
9. Now you can go back to your Recycle Bin, right click inbox.bak, and choose RESTORE.
10. That file inbox.bak should now be in the folder you just found.
11. Right click inbox.bak and rename it inbox.dbx
12. Now open Outlook Express and your inbox messages should be restored.
OR if that doesn’t work ..
 From the Outlook Express Top Menu, click File > Import > Messages > Choose the email program you use
 If it was Outlook Express 6, then choose >Import Mail from an OE6 Store Directory
 > Click OK, and browse for that folder you just found
 > Click and choose inbox.dbx or whichever file you want to restore
 and voila, those messages should be restored.
Hope this helps.