gibberish in html files

I saved a file with a .asp extension, using Visual Studio 2013.  When i opened the file the next day, all of the non-alphanumeric characters were replaced by strings of characters starting with + and ending with -. For example, <%" was replaced by +ADwAJQBA-.  
+ACM- seems to be the replacement for !
+ADwAIQ- seems to replace <

so combinations of characters get different replacements than single characters.

Two questions:

1. how do i restore my file?
2. how do i prevent this from happening again?

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Alexandre SimõesManager / Technology SpecialistCommented:
Apparently you're not alone. Searching on Google I found some other websites with the same problem ( but I have no explanation for what happened there.
Chances are that you had some encoding issues but which I don't know.

I'll keep an eye on this thread :)

David Johnson, CD, MVPOwnerCommented:
.asp isn't html and the converse is also true.. was it in fact an .asp file that now has been turned into gibberish?
DilettantesKeepAuthor Commented:
Yes it was really an ASP file.  I found over thirty different +Axxxx- values, and by comparing to a similar file (that i opened in WordPad in case VS is the problem) was able to search and replace to get my original file working. But now I make a backup first and cross my fingers whenever i open files in VS2013.

I too saw other examples of this problem, some were in html emails. I did not look on any malware solution sites, perhaps that is my mission the next time this happens.
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Scott Fell, EE MVEDeveloper & EE ModeratorCommented:
I was thinking this was a code page issue although never seen it.  But looking at msdn

The very top of your classic asp page should be

Open in new window

Then add the html code page info
<meta http-equiv="Content-type" content="text/html; charset=utf-8">

Open in new window

Content-Type: text/html; charset=UTF-8

Open in new window

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DilettantesKeepAuthor Commented:
Thank you Scott, that certainly looks like the answer - I'll make sure to put that in my pages. The MSDN article seems to be right on topic.
DilettantesKeepAuthor Commented:
Speedy accurate resolution to my problem - many thanks!
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