My first test was a self-built master version but I got into write permission trouble...
I just tested on Win Server 2012 with a Solr 6.5.1, and successfully did solr start, solr create, and even solr -e techproducts, when running from a folder with space in it. I also tried solr create -c foo -d folder and solr start -s "C:\path with space" and they both work.
Then I tried solr create -c foo -d "C:\path with spaces\to\conf", and that one failed with error
ERROR: Specified config directory C:\Users\jho\Desktop\solr not found in C:\Users\jho\Desktop\solr with space\server\sol
I don't know if that particular command used to work pre 6.5?
The script code in question is
"%JAVA%" %SOLR_SSL_OPTS% %AUTHC_OPTS% %SOLR_ZK_CREDS_AND_ACLS% -Dsolr.install.dir="%SOLR_TIP%" ^
-classpath "%DEFAULT_SERVER_DIR%\solr-webapp\webapp\WEB-INF\lib\*;%DEFAULT_SERVER_DIR%\lib\ext\*" ^
org.apache.solr.util.SolrCLI create_core -name !CREATE_NAME! -solrUrl !SOLR_URL_SCHEME!: -confdir !CREATE_CONFDIR! -configsetsDir "%SOLR_TIP%\server\solr\configsets"
I think the -confdir !CREATE_CONFDIR! is the sinner, it should be quoted, not?