Jerry Lau

I have the same situation as well.. tonnes of those

 **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)
   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

   **** Warning: Form stream has unbalanced q/Q operators (too many q's)

   **** This file had errors that were repaired or ignored.
   **** The file was produced by:
   **** >>>> TCPDF 6.2.13 (http://www.tcpdf.org) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.

find the owner of the course and notify them

Or what you can do is to announce a downtime for maintenance and create a backup to the database. Then do a search and replace of the string needed and import it back into the database. That is what I did

Not moodle specific but more like php/apache setup.. I read that is the preferred method..

delete your sessions, temp, cache, localcache, and trashdir content in your moodledata folder and restart both the web and db server.

make sure there is enough room

what version were you upgrading from?