When uploading a file using the Attachment link, the local path of the file from the client workstation is displayed as a description of the attachment (for example 'C:\folder\test.txt', instead of 'test.txt' only).
This is an Internet Explorer security setting issue.
'Include local directory path when uploading files to a server' is enabled.
Resolving the problem
From your Internet Explorer browser, go to Tools > Internet Options > Security Tab > click 'custom level' button > Find 'Include local directory path when uploading files to a server' under Miscellaneous > select disable > click OK/Apply/OK.
Make sure you select the correct security zone for your Maximo site.