Leider hakt es noch an einem Fehler den ich nicht verstehe.
Zuerst habe ich bei jedem Versuch das Literaturverzeichnis gelöscht und biber ausgeführt
Process started INFO - This is Biber 2.12 INFO - Logfile is 'Thesis.blg' INFO - Reading 'Thesis.bcf' INFO - Found 9 citekeys in bib section 0 INFO - Processing section 0 INFO - Looking for bibtex format file 'Literatur/Literaturverzeichnis.bib' for section 0 ERROR - Cannot find 'Literatur/Literaturverzeichnis.bib'! INFO - ERRORS: 1 Process exited with error(s)
Wenn ich mit Citavi Exportiere und die Zeichenkodierung ISO Nutze:

BibTeX:
Process started INFO - This is Biber 2.12 INFO - Logfile is 'Thesis.blg' INFO - Reading 'Thesis.bcf' INFO - Found 9 citekeys in bib section 0 INFO - Processing section 0 INFO - Looking for bibtex format file 'Literatur/Literaturverzeichnis.bib' for section 0 INFO - LaTeX decoding ... INFO - Found BibTeX data source 'Literatur/Literaturverzeichnis.bib' INFO - Overriding locale 'de-DE' defaults 'variable = shifted' with 'variable = non-ignorable' INFO - Overriding locale 'de-DE' defaults 'normalization = NFD' with 'normalization = prenormalized' INFO - Sorting list 'none/global//global/global' of type 'entry' with template 'none' and locale 'de-DE' INFO - No sort tailoring available for locale 'de-DE' INFO - Writing 'Thesis.bbl' with encoding 'UTF-8' INFO - Output to Thesis.bbl Process exited normally
Overfull \hbox (3.22041pt too wide) detected at line 12 Underfull \vbox (badness 10000) has occurred while \output is active [] LaTeX Warning: Label(s) may have changed. Rerun to get cross-references right.
Wenn ich Citavi mit UTF exportieren lasse:

BibTeX:
Process started INFO - This is Biber 2.12 INFO - Logfile is 'Thesis.blg' INFO - Reading 'Thesis.bcf' INFO - Found 9 citekeys in bib section 0 INFO - Processing section 0 INFO - Looking for bibtex format file 'Literatur/Literaturverzeichnis.bib' for section 0 INFO - LaTeX decoding ... INFO - Found BibTeX data source 'Literatur/Literaturverzeichnis.bib' WARN - Name "AutorA, A und AutorB, B und AutorC, C" has too many commas: skipping name WARN - Name "AutorA, A und AutorB, B und AutorC, C" has too many commas: skipping name WARN - Name "Alazmani, Ali und Roshan, Rupesh und Jayne, David G. und Neville, Anne und Culmer, Peter" has too many commas: skipping name WARN - Name "Sjoerdsma, W. und Herder, J. L. und Horward, M. J. und Jansen, A. und Bannenberg, J. J. G. und Grimbergen, C. A." has too many commas: skipping name INFO - Overriding locale 'de-DE' defaults 'variable = shifted' with 'variable = non-ignorable' INFO - Overriding locale 'de-DE' defaults 'normalization = NFD' with 'normalization = prenormalized' INFO - Sorting list 'none/global//global/global' of type 'entry' with template 'none' and locale 'de-DE' INFO - No sort tailoring available for locale 'de-DE' INFO - Writing 'Thesis.bbl' with encoding 'UTF-8' INFO - Output to Thesis.bbl INFO - WARNINGS: 4 Process exited normally
Overfull \hbox (3.22041pt too wide) detected at line 12 Citation 'testzeit' on page 1 undefined Citation 'testbuch' on page 1 undefined Underfull \vbox (badness 10000) has occurred while \output is active [] There were undefined references. Label(s) may have changed. Rerun to get cross-references right. Please (re)run Biber on the file:(biblatex) Thesis(biblatex) and rerun LaTeX afterwards.
Für mich die leichte Lösung ich lasse es einfach im ISO Format
Aber warum kann ich dort kein UTF auswählen.
Beider male wenn ich die Literaturverzeichnis.bib in Texmaker öffne wird sie anscheinend auch mit UTF-8 geöffnet
(jedenfalls steht unten rechts immer ein kleiner UTF-8)
Vielen Dank