I discovered this problem today when using Excel 2013.  I hadn't used Excel in about 2 weeks, and did not have this issue before.  I opened a file I've used periodically for the past year.  I entered "5" into an empty cell and the number was immediately replaced with "Odysseus".  I created a new, blank file and had the same result.

The number five is replaced as soon as I hit space after typing 5.  I do not need to tab/return out of the cell for it to take effect like date format changes, etc.

Data entered and result (quotes not included):

"5"  returns "Odysseus"

"15" returns "15"

"50" returns "50"

"=5+5"  returns "=+Odysseus+Odysseus"

"5 Test" returns "Odysseus Test"

"Test 5" returns "Test Odysseus"

"5/11/2015" returns "Odysseus/11/2015"  (Odysseus appeared as soon as I hit the first "/")

What I have done so far

- Created a restore point to 5/1/2015.  I may need to go back further than this though.

- Ran AVG antivirus.  A trojan was discovered and quarantined - MalSign.Generic.3F0   Unclear if this is related

- Uninstalled / Reinstalled MS Office suite.  Uninstalled using the Microsoft tool to remove MS Office Suite.(filename:  O15CTRRemove.diagcab)

I am still getting this issue.

Any help would be greatly appreciated.

Mark

Could it be AutoCorrect?

Select File > Options.

Select Proofing in the navigation pane on the left.

Click AutoCorrect Options...

In the AutoCorrect tab, enter 5 in the Replace box.

Does Excel automatically enter Odysseus in the With box? If so, click Delete.

Click OK, then OK again.

Ahhh thanks so much!  Didn't even think to look there.  Haven't used that feature in any Office program in a long, long time.  There was a second entry in the list that replaced "a" with my niece's full name.  Maybe she got into there somehow and messed it up without knowing (or telling me) about it.  Although it is in an obscure menu path, so I don't know how she would have stumbled onto it by accident.  And I highly doubt she even knows about the feature to have done it on purpose.  And why "Odysseus"?  Just a bunch of weird coincidences.

Regardless, its fixed and I thank you for your help!

Mark 

• Edited by markmark1 14 hours 22 minutes ago