I have a strange issue regarding a Typo3-Installation (version 6.1). The frontend works fine, but the backend-login is blank (white screen). When I look into the source of the blank page, there is everything there, compared with a working 6.1-instance. I know, a blank backend comes mostly from some PHP-Errors, but in this case I can't find any. The install-tool says, that everything is fine. There are no javascript-errors in the blank login and I deleted the typo3-caches. I also tried with different browsers on different machines - still a blank page, but source is there. Do you have any hints or ideas?
Updating to the latest version (6.2.17) solved that problem.