SymptomsIn Trados 2015, you may find that everything displays fine when you insert the source text into the translation field, but when you actually start typing over the translation, a seemingly random set of characters in that sentence are replaced with boxes (e.g. something like に対して becomes に口して)
In 7zip, you may find that filenames inside zip files are completely illegible: for example, "＜原稿＞英訳用%u3000申請リリース案" becomes something like "üâî┤ìeüäëpû¾ùpü@". (This is particularly problematic if you want to send the files back to the customer with the same filenames as you received them!)
A simple workaround is to download and install locale emulator, which lets you right-click the shortcuts to 7zip or Trados and select "Run in Japanese", which fixes the above problems and -so far as I can tell- has no other significant impact on the performance of the programs at all.
One problem on Windows 10 (and probably anything 8 upwards) is that you can't use the RMB to access the locale emulator from the start menu; however, locale emulator lets you make a shortcut that essentially performs the above automatically:
First, right-click your shortcut (to Trados or 7Zip, or whatever else you are trying to fix) and click "Open file location" (for the win 10 start menu, right-click, then select "More"->"Open file location". Typically for windows, this will only display the shortcut-containing folder.. You will need to right-click that shortcut and again select "Open file location").
Next, in a new window, find the locale emulator folder (the folder you unzipped from the earlier download) drag the application file onto locale emulator; this gives you an option "Create shortcut". By doing this, you make a shortcut (on the desktop) that will open the application in your locale of choice (for me, Japanese), even better, this shortcut can sit in the start menu without any problems (RMB on shortcut, "pin to start").
What's the deal with this problem?
The problem evidently is one of the OS locale, given that the fix is a locale emulator. Consequently, you should theoretically be able to fix the problem by changing your OS locale; however, there are a number of reasons you might not want to do this. Personally, I use Windows 10's Cortana assistant, and I like to do that in my mother tongue. Having system menus in English also helps speed maintenance issues.
With regards to 7Zip I'm not expert as to what restrictions exist with filenames etc.; however, for Trados I'm a little more skeptical. By its premise, Trados is a multilingual tool, and yet it handles the issue of OS locale quite poorly compared to non-specialist tools such as Microsoft Word (which admittedly has the benefit of being designed by the same company as the OS itself), or most web browsers.
This leads me to the other workaround I tried, which is a translation tool called Felix that works right inside MS Word. Because Word doesn't have any problem with locales, Felix doesn't suffer from the above problems. Felix isn't without its problems of course, and using Felix in a workflow that requires the use of Trados package files will add an extra layer of frustration. Nonetheless, Felix is probably my favorite tool after Trados for translating (and it very nearly tops it due to its ease of use).