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"There was too much rumor."
"There were too many rumors."

"Rumor" is countable and uncountable. Could it be that both sentences are standard English?
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SheltieBites"There were too many rumors."
Only this one is correct.
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SheltieBites"A military spokesman said that many of the charges were based on rumor and that the military would investigate the accusations of abuse against women."
In the above sentence "rumor" is used in a general sense and it means "unverified information":

A military spokesman said that many of the charges were based on unverified information...
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http://www.nytimes.com/2011/04/09/world/middleeast/09egypt.html?pagewanted=all
"A military spokesman said that many of the charges were based on rumor and that the military would investigate the accusations of abuse against women."

Many dictionaries have consistently suggest that an uncountable version of "rumor" exists, possibility under limited circumstances?
 ozzourti's reply was promoted to an answer.
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Then, both of these:

"There was too much rumor."
"There were too many rumors."

are standard English, but mean different things?
I'll admit that the second sentence seems more natural to me although I did find instances of "too much rumo(u)r" in Google Books:

He sees them in terms of too much rumor and too much risk...
One employee appeared to sum up the sentiments of many of the focus group participants when she remarked that "[frontline] employees had too much rumor and too few facts about the change process."
Too much rumor was getting out via hospital employees, and he didn't want more erroneous information leaking out.
... either because she's still worried that I will share her information with others, or that too much rumor and speculation will chase Luke Nelson away.
"Too little knowledge and too much rumor" is one fairly accurate way to describe most Americans' conceptions of contemporary developments in science, especially nuclear science.
He had to see Goldwater personally, but not at the White House. There was too much rumor already.
However, too little is known about Abu Nidal, and his name attracts too much rumor to make a definitive judgment.
There was too much rumor, too little regard for the PRA.
Fourthly, there is far too much rumour about the Government introducing a capital freeze before independence comes and there are people who are being, perhaps, super-cautious that are thinking of moving funds before ever independence...
Sometimes, for me, there is too much rumour in the book, but nothing major.
However, the point has been reached when there has been just too much rumour and confusion...

Indeed, in all those examples "rumor" is uncountable and is used in a way similar to "information".