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?

TIA
DilettantesKeepAsked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Alexandre SimõesManager / Technology SpecialistCommented:
Apparently you're not alone. Searching on Google I found some other websites with the same problem (http://www.christianrevivalcentre.org/aboutthepastor.aspx) 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 :)

Cheers
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.
The 7 Worst Nightmares of a Sysadmin

Fear not! To defend your business’ IT systems we’re going to shine a light on the seven most sinister terrors that haunt sysadmins. That way you can be sure there’s nothing in your stack waiting to go bump in the night.

Scott Fell, EE MVEDeveloper & EE ModeratorCommented:
I was thinking this was a code page issue although never seen it.  But looking at msdn https://msdn.microsoft.com/en-us/library/dd565635(v=vs.85).aspx

The very top of your classic asp page should be
<%@LANGUAGE="VBSCRIPT" CODEPAGE="65001"%>

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

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

Open in new window

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
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!
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Web Languages and Standards

From novice to tech pro — start learning today.