Please see https://issues.apache.org/jira/browse/TIKA-1002.

Tika cannot decode the unicode-1-1-utf-7 encoding.

These might be the mail headers involved:

Subject: Benachrichtigung
=?unicode-1-1-utf-7?Q?+APw-ber
Zustellstatus
(Relay)?=

--9B095B5ADSN=_01C542A985ACDA72000063DAApollo.foobarbaz
Content-Type: text/plain; charset=unicode-1-1-utf-7




ERROR 2012-10-04 10:13:01,589 - de.uplanet.lucy.server.searchengine.index.SearchIndexCompiler[SearchIndexCompilerThread]
Unexpected RuntimeException from org.apache.tika.parser.microsoft.OfficeParser@3b7304b
org.apache.tika.exception.TikaException: Unexpected RuntimeException from org.apache.tika.parser.microsoft.OfficeParser@3b7304b
at org.apache.tika.parser.CompositeParser.parse(CompositeParser.java:244)
at org.apache.tika.parser.CompositeParser.parse(CompositeParser.java:242)
at org.apache.tika.parser.AutoDetectParser.parse(AutoDetectParser.java:120)
at org.apache.tika.Tika.parseToString(Tika.java:380)
at de.uplanet.lucy.server.docplug.tika.TikaDocPlug.prepare(Unknown Source)
at de.uplanet.lucy.server.searchengine.index.AddFileIndexAction.performAction(Unknown Source)
at de.uplanet.lucy.server.searchengine.index.SearchIndexCompiler.a(Unknown Source)
at de.uplanet.lucy.server.searchengine.index.SearchIndexCompiler.processQueuedActions(Unknown Source)
at de.uplanet.lucy.server.searchengine.index.SearchIndexCompiler$SearchIndexCompilerThread.run(Unknown Source)
Caused by: java.lang.RuntimeException: Encoding not found - unicode-1-1-utf-7
at org.apache.poi.hsmf.datatypes.StringChunk.parseAs7BitData(StringChunk.java:155)
at org.apache.poi.hsmf.datatypes.StringChunk.parseString(StringChunk.java:86)
at org.apache.poi.hsmf.datatypes.StringChunk.set7BitEncoding(StringChunk.java:74)
at org.apache.poi.hsmf.MAPIMessage.set7BitEncoding(MAPIMessage.java:421)
at org.apache.poi.hsmf.MAPIMessage.guess7BitEncoding(MAPIMessage.java:380)
at org.apache.tika.parser.microsoft.OutlookExtractor.parse(OutlookExtractor.java:80)
at org.apache.tika.parser.microsoft.OfficeParser.parse(OfficeParser.java:210)
at org.apache.tika.parser.microsoft.OfficeParser.parse(OfficeParser.java:161)
at org.apache.tika.parser.CompositeParser.parse(CompositeParser.java:242)
... 8 more
Caused by: java.io.UnsupportedEncodingException: unicode-1-1-utf-7
at java.lang.StringCoding.decode(StringCoding.java:170)
at java.lang.String.<init>(String.java:443)
at java.lang.String.<init>(String.java:515)
at org.apache.poi.hsmf.datatypes.StringChunk.parseAs7BitData(StringChunk.java:153)
... 16 more

Ref.:
http://tools.ietf.org/html/rfc1642
http://tools.ietf.org/html/rfc2152