Searching a string in eclipse workspace
Solution 1:
At the top level menus, select 'Search' -> 'File Search' Then near the bottom (in the scope) there is a choice to select the entire workspace.
For your "File search has encountered a problem", you need to refresh the files in your workspace, in the Project/Package Explorer, right click and select "Refresh" at any level (project, folder, file). This will sync your workspace with the underlying file system and prevent the problem.
Solution 2:
Press Ctrl + H, should bring up the search that will include options to search via project, directory, etc.
Ctrl + Alt + G can be used to find selected text across a workspace in eclipse.
Solution 3:
Ctrl+ H, Select "File Search", indicate the "file name pattern", for example *.xml or *.java. And then select the scope "Workspace"
Solution 4:
A lot of answers only explain how to do the search.
To view the results look for a search tab (normally docked at the bottom of the screen):