Similar problem here - I had a trivial example running on a giga display, now "Arduino_H7_video.h" is missing.
FQBN: arduino:mbed_giga:giga
Using board 'giga' from platform in folder: C:\Users\Patty\AppData\Local\Arduino15\packages\arduino\hardware\mbed_giga\4.1.1
Using core 'arduino' from platform in folder: C:\Users\Patty\AppData\Local\Arduino15\packages\arduino\hardware\mbed_giga\4.1.1
Detecting libraries used...
C:\Users\Patty\AppData\Local\Arduino15\packages\arduino\tools\arm-none-eabi-gcc\7-2017q4/bin/arm-none-eabi-g++ -c -w -g3 -nostdlib @C:\Users\Patty\AppData\Local\Arduino15\packages\arduino\hardware\mbed_giga\4.1.1\variants\GIGA/defines.txt @C:\Users\Patty\AppData\Local\Arduino15\packages\arduino\hardware\mbed_giga\4.1.1\variants\GIGA/cxxflags.txt -mcpu=cortex-m7 -mfloat-abi=softfp -mfpu=fpv5-d16 -w -x c++ -E -CC -DARDUINO=10607 -DARDUINO_GIGA -DARDUINO_ARCH_MBED_GIGA -DARDUINO_ARCH_MBED -DARDUINO_LIBRARY_DISCOVERY_PHASE=1 -IC:\Users\Patty\AppData\Local\Arduino15\packages\arduino\hardware\mbed_giga\4.1.1\cores\arduino -IC:\Users\Patty\AppData\Local\Arduino15\packages\arduino\hardware\mbed_giga\4.1.1\variants\GIGA -DCM4_BINARY_START=0x60000000 -DCM4_BINARY_END=0x60040000 -DCM4_RAM_END=0x60080000 -IC:\Users\Patty\AppData\Local\Arduino15\packages\arduino\hardware\mbed_giga\4.1.1\cores\arduino/api/deprecated -IC:\Users\Patty\AppData\Local\Arduino15\packages\arduino\hardware\mbed_giga\4.1.1\cores\arduino/api/deprecated-avr-comp -iprefixC:\Users\Patty\AppData\Local\Arduino15\packages\arduino\hardware\mbed_giga\4.1.1\cores\arduino @C:\Users\Patty\AppData\Local\Arduino15\packages\arduino\hardware\mbed_giga\4.1.1\variants\GIGA/../GIGA/includes.txt C:\Users\Patty\AppData\Local\Temp\arduino\sketches\4DE351FBA073E365881201D43E8625F9\sketch\Demo-touch_detector.ino.cpp -o nul
C:\Users\Patty\Documents\OneDrive - Emory University\Customers & Projects\Outside departments\Environmental Science\Debjani Sihi lab\Soil sample O2\Arduino code\Giga Display startup\Demo-touch_detector\Demo-touch_detector.ino:1:10: fatal error: Arduino_GigaDisplay_GFX.h: No such file or directory
#include "Arduino_GigaDisplay_GFX.h"
^~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
Alternatives for Arduino_GigaDisplay_GFX.h: []
ResolveLibrary(Arduino_GigaDisplay_GFX.h)
-> candidates: []
exit status 1
Compilation error: Arduino_GigaDisplay_GFX.h: No such file or directory